I think another important point is that Hackathons are what you make it.

I like going to them to meet new people and try out a new idea. If I want to fall asleep, I can. I'm not "forced" into doing anything I don't want to do.

I usually work 14 hours or so, go to sleep, wake up, shower, then work again - doing this for 2 or 3 days hardly makes me feel like crap or messes with my sleep schedule.