A lot happens while your asleep. It's not just your brain repairing itself, although you'd think this would be important enough. In college, at the end of a few hours of study, I'd have some vague understanding of the material. After a full night of sleep, the next day, the information was sometimes clear as day.

Additionally, I'm convinced that your dreams, whether you remember them or not, influence your consciousness. That great idea you had may be a derivative of some really strange thoughts that went through your head while you were asleep.

The point is that sleeping isn't wasted time. There's really important things going on and the ones sleeping those 30 more days a year are probably going to get more out of their sleep than those staying awake for that time.