Well we know he has a pretty fucked up sleep cycle, staying up late very often apparently has a strong correlation with people who are more psychotic, manipulative and self admiring (tips a lot of boxes for Phil right?). There was even a Nobel prize winning article about this exact same topic, you can read a little bit about a small excerpt of that article
here.
It briefly touches upon the concept of the dark triad, which is a set of three traits commonly associated with narcissism and other similar traits,
View attachment 2150119
So I don't really know a whole lot about complex psychology, but my understanding would be that Phil self-validates his night time habits by thinking or saying malevolent phrases or words to himself and/or others to comfort himself into thinking there are no problems with his perpetual habits and lifestyle resulting him staying up late for hours on end.
In a way, if he was to get more hours of sleep, he would be less of a shithead and more upbeat, energetic (haha hardly I think for him) and pahsative overall to how he normally is.