There's some usefulness to it; but the thing is, if it's an easy to find stupidity, then it's a stupidity that you already know to be a stupidity. It teaches you comparatively little about good or bad judgment.
A hard-to-find stupidity is one that's subtle and difficult to recognise. It's one that is not obviously a stupidity, one that you do not easily recognise on sight. Therefore, a hard-to-find stupidity will teach you more about the difference between good and bad judgment than an easy-to-find one...
Also, the importance of the stupidities is largely irrelevant to the stated goal - the importance of the consequences has little effect on how good or bad the judgment behind the decision was.
(Now, if you're trying to fix stupidities, instead of learning from them, then the large, important, easy-to-find ones are the ones to look at...)
if it's an easy to find stupidity, then it's a stupidity that you already know to be a stupidity. It teaches you comparatively little about good or bad judgment
Eh, I don't know about that. Many similar stupidities look radically different in different contexts. It's hard to overstate the effect of formulations, frameworks, and angles of view on the perception of basically the same things. I think what Charlie Munger was doing was looking for patterns which he could then discern in unexpected places.
Easy-to-find vs hard -to-find is mostly a difference in context. Put Waldo into a picture of a night sky and, well...
Another month, another rationality quotes thread. The rules are: