I once saw a program on the Discovery Channel about sleep deprovation, and I believe they detailed the story of a man, a music teacher, who could not sleep. They showed the deterioration of intelligence, motor skills and speech. Eventually the man succumbed to his illness (which I have yet to define).
Scientists still aren't sure why we NEED sleep, but lack of it has proven to be a bad thing, over and over again. I wouldn't know why anyone would want to do that to themselves.