points, especially the excellent N95 masks...or your terminology "...even if you had the best available." ;-)
But, be that as it may...I have observed my own G-kids and their class/play-mates...with all their laughing during recess (while wearing masks), I couldn't make out how "traumatized" they were, but I'm sure it wasn't too much...as for learning, the G-Kids are doing just fine with their grades and the parents aren't upset either.
On the medical side, I constantly refer to your thoughtfully linked "MIT Report" on how phenomenal an N95 mask can be, so all-in-all, I'm convinced on the Psychological, Educational and Medical levels that kids wearing effective, well-fitting masks during a deadly pandemic (not just for them, but all who come in contact with them) is the WISE DECISION.