I have many friends who are so wealthy they could easily live off their family's money for several generations. There are some who don't want to depend on their parents and actually make something of themselves. Of course there are others who go because their parents tell them to go. It seems to be looked down upon to just take your parents' money and do nothing with your life, or at least that's how it was from where I grew up (southern California).
It's a good place to meet people.
It's interesting.
It's fun.
I imagine you could get all that without having an obligation of coursework hanging over you, but I guess at that point that doesn't matter much either