I think I have found another unfortunate example of the epistemic hostility of modern life.
If an apparently reputable mycologist were to tell you that a wide range of fungi have been proven to have significant neuroprotective, antiviral, antibacterial, and/or immune boosting effects in humans, you would be surprised. At least, I was surprised.
Then you're forced to consider what to do with this information. A glance at your priors suggests that if this were true, you should already know about it. Doctors should be telling you to eat your mushrooms. Supplement companies should be marketing mushroom extracts at you just as they market vitamins.
A seperate set of priors points out that you did know that some fungi had antimicrobial effects (powerful antibiotic drugs) and others have powerful psychoactive effects. But you didn't know that these features would be general and you're not sure if you should assume that they are.
Then you consider the cynical Hansonian perspective that says doctors aren't really all that motivated to recommend that you consume cheap substances that keep you from needing to go to the doctor, and supplement companies might not make much profit selling you mushroom pills when you can just buy mushrooms.
Then you realize you have very little chance of successfully arbitrating between these perspectives. You're not even sure where to look to find out if mushrooms are really good for you and that you should be eating more of them. You could look at academic publications but you're not confident in your ability to interpret such findings, which tend to be highly narrow and specific, and apply them to your life. You could look at the ads of supplement companies that do sell mushroom extracts, but you wouldn't trust them.
So it's data that has a potentially significant upside that you can't really prove to yourself, despite the fact that all of the relevant information is in principle known to people and probably publicly available.