[opportune]

When I was a college student, I wasn't diligent enough to always do ungraded assignments. I'd do reading, but for actual questions I'd only do them maybe 50% of the time when preparing for a test on the material. And out of my peers I felt like even doing assigned reading and trying to do ungraded homework put me well ahead of the pack.

I think it's a maturity thing. Probably until I was ~24 I just didn't have the executive function to be able to do things like that. It seems beneficial to have graded assignments as a forcing function especially given some college students are literally teenagers.

Also, I took an accelerated math curriculum as a freshman where I went from never having written a proof/knowing how to prove something rigorously, to pretty good at it. The feedback from the assigned homework was absolutely crucial in helping me learn these skills. It's easy to follow a proof from the answer section, but since there are usually several ways to prove something, it doesn't always help just to see an answer, plus you don't know what kind of divergences/hand waves are acceptable or not without feedback.