Besides, being around a pack of intelligent, highly motivated people (what their admissions select for) 24/7 was incredibly fun. I mean, you're around people who build CPUs out of 7400 ttl chips, people who build stereo equipment from scratch just because it's fun, people who build a working railroad running through the dorms, and on and on. If you want to see what it was like, see the movie "Real Genius", which was based on events at Caltech. The movie exaggerates, but not as much as you might think :-)
Edit: I also have to admit that the embarrassment of failing was a motivator that wouldn't exist if I attended remotely, along with the shared camaraderie of working on and succeeding at something hard.