As above, so below. These lines of thinking sees sleep as a hygiene factor for maintaining bio stasis. We also process experiences and “simulate” effects of potential actions in the waking state. These “software-level” sleep activities seems less quantifiable in terms of sleep-time efficiency. If I get an evolutionary advantage from better consolidated experiences through longer dream sessions, how would that compare with more “face-time” with lions and famines in my waking state? There is a nasty “all things being equal” fallacy hidden in this line of thinking.