The "God told me" modality, when you can pull it off, allows statements to be made which invite absolutely no disagreement. This is of course very very useful in the right context.
This is not my experience growing up fundamentalist Christian in a country/society where atheism is unthinkable.
The God told me modality doesn't invoke such carte blanches in general. It's not a free pass to do anything. Very religious societies wouldn't actually work if this was a thing that actually happened.
One time, a bunch of particularly indecisive friends had started an email thread in order to arrange a get-together. Several of them proposed various times/locations but nobody expressed any preferences among them. With the date drawing near, I broke the deadlock by saying something like "I have consulted the omens and determined that X is the most auspicious time/place for us to meet." (I hope they understood I was joking!) I have also used coin-flips or the hash of an upcoming Bitcoin block for similar purposes.
I think the sociological dynamic is something like: Nobody really cares what we coordinate on, but they do care about (a) not wanting to be seen as unjustifiably grabbing social status by imposing a single choice on everyone else, and (b) not wanting to accept lower status by going along with someone else's preference. So, to coordinate, we defer the choice to some "objective" external process, so that nobody's social status is altered by it.
An example where this didn't work: The Gregorian calendar took centuries to be adopted throughout Europe, despite being justified by "objective" astronomical data, because non-Catholic countries thought of it as a "papal imposition" whose acceptance would imply acceptance of the Pope's authority over the whole Christian church. (Much better to stick with Julius Caesar's calendar instead!)
I use the same strategy sometimes for internal coordination. Sometimes when I have a lot of things to do I tend to get overwhelmed, freeze and do nothing instead.
A way for me to get out of this state is to write down 6 things that I could do, throw a die, and start with the action corresponding to the dice outcome!
Nice! I think about doing this, sometimes, but never end up actually doing it. (Partly because I don't always need it, once I recognize the problem; but probably partly because if I'm procrastinating then I'm probably motivated to keep procrastinating rather than settle on anything.)
Gods are more practical when specialized, with commandments that are easy to reason about. This way, their will more easily becomes common knowledge among believers, channeled through their coordinated action.
Meditation/prayer can seemingly be used to talk more directly to system 1. System 1 reports that it is a different kind of processing but doesn't have any access to magic knowledge and that other claims about talking to system 1 probably involve bog standard delusions of grandeur and other biases. It definitely doesn't use language and the comm channel is weirdly insanely high resolution in some dimensions and insanely low resolution (single bit) in others. It seems to agree that the parallel/serial processing metaphor is better than most as far as the system 1/2 distinction goes, which it also thinks only captures some useful dimensions.
Why don't you just tell people to coordinate instead of adding the extra indirection of an mental entity? I guess it serves as an anchor point for the group to fall back on for the coordination. Hospitals coordinate on helping patients. Government coordinate on running a nation. Those are solid anchor points that everyone can see and agree too. A mental entity can be too vague and whimsical unless you spend the time to work on establishing it as a religious institution, creating a lot of materials for people to anchor on, basically an entire world model. This actually seems like what the EA community is built on. There is this prior knowledge that people need to read up on in order to participate. It is multi-disciplinary given the nature of the discussion, which is not much different from special interest groups.
(low-effort post)
The following is not supposed to be an account of all religion, only a very specific thing that happens sometimes.
In logic, a "modality" is a qualifier you can put on a statement, which changes the rules for interacting with that statement. For example, "possibly X", "necessarily X", "I believe X", "I know X", and so on.
I'm going to use the term "modality" somewhat loosely, to refer to different modes of interaction with statements.
I think there's a part of rationality that could be described as "the search for the trustworthy modality". For example, "scientifically" is a pretty good modality. It has a set of rules around it which has, historically, been wildly and vividly successful in comparison with other modalities.
However, rationalists have some problems with the "scientifically" modality, especially in contrast to a "bayesian" modality.
This quest of finding useful modalities isn't really restricted to rationalists, of course. Basically all humans are looking for the best ways to have their words understood, and looking to understand others. Qualifiers like "I believe" are important tools which allow opinions to be expressed without introducing raw contradiction into the conversational context.[1]
The "God told me" modality, when you can pull it off, allows statements to be made which invite absolutely no disagreement. This is of course very very useful in the right context.
Looking around at the world, it seems clear that many of our problems are coordination problems. War is the most obvious -- it could simply stop and everything would be better! Of course, in these parts, we call the general problem Moloch.
So, catching a glimpse of how much better it could be if everyone would coordinate, it might seem easy to call it a glimpse of God's will. And you can see that if everyone would simply listen to this Will, things would be much better.
So you set out preaching the benefits of this modality, and try to create a community of practice around it.
It almost doesn't matter exactly what outcome we coordinate on, so long as we coordinate. So you might try to create a very viral form of the God modality. And you might have a lot of arbitrary practices in your community of practice, because you're implicitly more focused on coordinating on something than on making sure you've coordinated on the best possible thing.
Once, at a LessWrong meetup in Los Angeles, a beach bum prophet came to the meetup with a follower or two. They excitedly told us about how the prophet guy was leading bible studies on the beach, and how each of them had turned their lives around because of it. The prophet told me a few stories about God telling him things, which sadly I don't remember in much detail now. But it did include one instance of God calling him on his BS prophecy, actually.
Of course, I've experienced religious people talking about "talking to God" many times. But only rarely do they have the courage[2] to claim that God said anything back. And even then, it seems to me like a soft echo of the ecstatic relationship with God which the beach bum prophet had.
I'm not claiming this is literally true (certainly not of all religions), but it gives me a mental image of religions being started by prophets who see this potential for coordination. They get a few people listening to them, and they think how great it would be if everyone in the world would get on the same wavelength. So they try to spread. But of course the religious practice that gets spread is far from the actual mental algorithm being used by the original prophet (to varying degrees, depending on the case).
(And, also of course, the mental algorithm used by the prophet probably wasn't that great in the first place.)
Saying "X" conveys the same information as "I believe X", from a Bayesian perspective; but if one person says "X" and another person says "not X", a listener cannot accept what both have said; while if one person says "I believe X" and another says "I believe not-X", a listener can believe both statements.
So, the "belief" modality allows us to preserve a conversational norm of "by default, what each person says is assumed as truth in the conversation going forward, unless explicitly questioned".
Otherwise, stating contradictory beliefs would invite argument more than it does, which would sometimes be inefficient.
(or whatever you want to call it!)