What amazed me was how much the study of drawing is a good exercise in rationality. Not only do you have to learn to observe reality (this is surprisingly hard), but you have to pretty much scrap your entire model of how you think drawing works. (Almost everything you will naturally gravitate towards is wrong).

My prior confidence (relative to what the follow-up posts have to say) of the first sentence above is low. Yes, you have to learn how to observe reality, but you'll do so as an artist, not as a more generalized agent. Drawing may call your attention to previously-unnoticed details, but these details may be irrelevant for all purposes other than drawing them. To that extent, learning to draw will not add epistemic benefit.

And the second listed benefit above (you will learn the truth about how drawing works) is not a benefit either, except in the narrow sense that it involves updating your map. This is helpful, but it's not a rationality technique (i.e., something that aids in map-updating generally).

I look forward to reading the follow-ups, because if I am wrong then it will give me an opportunity to become less so. And the existence of repeating meet-ups devoted to drawing is evidence against my claim.