So I have gone through some sleep deprivation and came to a stunning realization. Sleep is not only a biological need but a psychological one as well. Even if we didn't physically need sleep, we would probably do it anyways if only to preserve our own sanity. Imagine going through life without any sleep at all, there would be nothing to place between days and events. No lapses of consciousness to separate your third birthday from your twenty first.
It would also probably be infinitely more difficult to get over certain events, relationships or even deaths because technically it all happened within that same conscious run through. I plan on going to bed after this post and I will probably wake up thinking this idea is stupid but whatever.