Sleep is for resting and recovering. You need sleep after say, a hard workout in order to requvinate and get stronger.
Now that I think about it, back in Highschool I used to sleep for about five hours or something, wake up, get ready and go to school, finish it, then go to wrestling practice and finish it, go home and do homework (or take a nap, then do it and go to bed).
I’m not sure if I was tired since I didn’t get enough sleep or something or if my practice had anything to do with it. I do know if you’re doing strength training you need rest to grow and get stronger.