> I'd rather just work and spend my money and experience things during that time.

That makes sense if the things you enjoy cost a lot. But not everyone needs a lot of money to do things they enjoy. For those people, the real cost of having a day to day job is time. For example, I may really enjoy biking and that is a hobby which does not require much money - but it does need daylight and with a full time job you lose the majority of that.