I was socially anxious in school so I didn't really experience that much of the last three.
regarding the first one, it's almost a tautology that you are being habituated into doing things you are ambivalent about for reasons you may not fully understand. perfect practice for the day job you get after graduating, really.
on the other hand, my self-actualized programmer friend - who never went to school and works on his own projects - occasionally has a tinge of insecurity because he never took a compiler class.
* it forces you to take classes that are good for you but you probably wouldn't take on your own
* social connections
* space to experiment on who you are as a person
* chance to get laid