Can't we simplify and say that the point of trade is to alter the entire system so that the final state is of higher utility to both participants than the initial state?

You have 2 apples and I have 2 oranges, but we both prefer the state where we have 1 of each fruit.

We both work 1 hour in the mines and 1 hour on the fields, but we both prefer the state where the skillsets of individuals overlap less.

At the end of your list the point of trade still exists, it's just the list of viable trades has been reduced.

1. Yes, precious metals are used as stores of value, however they are also used in electronics and in jewelry (which functions as a way to signal wealth). So I don't consider them counterexamples.
2. It's fair for you to believe that, but you're probably using a lot of weak evidence so it's hard to communicate that evidence to me. I'm just saying that what you did share wasn't sufficient to shift my opinion.

I'm considering buying this book. I would appreciate opinions from anybody who cares to answer.

How does this book compare to the sequences; does it explore topics which aren't covered by the sequences?

Does it function well as an introduction to rationality, as something which I could lend out to friends?

Why do you think that transactions are a poor proxy? I don't fully buy into the "store or value" idea. My uneducated opinion is something can only store value if it has an underlying use. Facilitating black markets is certainly an economically valid use. 

I'm confused by your second paragraph. Perhaps some of it is intended as a response to my answer to your first question? The primary argument which I can identify is that AI safety is not motivated by profit, but by saving the world. Saving the world requires money. Many people working on AGI probably think it will have an enormous positive impact on the world, so I can equally claim that they might not even ask for salary. 

I don't find you're argument convincing. It requires a lot of conditionals and appears to contain much room for error/oversight. You might be right but it doesn't serve me to speculate deeply into this topic, I'm content with not knowing.