Self-regulation of sleep
When it is listed as one of the new factors that college students can determine for themselves, sleep is considered a good thing. Because of numerous personal and physical benefits, among which is the theory that sleep itself increases self-regulation, more sleep is equated with better self regulation and time management. If you have time to sleep adequately, you are clearly getting your homework done on time, and fulfilling all other obligations.
On the other hand, there is a kind of quiet esteem for those students who have the reputation of "never sleeping" because they do so many extra curricular activities and they perform well academically. This goes in accordance with the idea proposed as advice to many beginning fiction writers, which is to give up sleep in exchange for quiet, peaceful writing time.
Sleep is interesting as a self-regulation resource, then, because it is one of the few things which can be up-regulated and down-regulated, with positive results for each.