I don't think it's necessarily incompatible even if it seems contradictory unless there's research that quantifies the harm as a function of sleep deficit. Could easily be some range of sleep deprivation in which you're just bad at things, you move slow, and you're unmotivated. Intuitively we'd think that it's directly proportional to the amount of sleep deprivation, but I don't know if I've seen research that makes that claim. It would be interesting to see more papers that lead to a model of the benefit of sleep as a function of the amount of time slept.