Yea. I've always figured that from an evolutionary standpoint it made some decent sense that you'd people to have slight but meaningful differences in their preferred sleeping patterns. That way you have in the tribe or group at least one person who's alert and energetic at nearly all times or at least can be if necessary. And even today, many jobs require wakefulness outside of the ordinary office hours. But, IME, you can see the toxicity of the "early riser" culture by how much it can pervade even in these relatively abnormal work contexts.