Using season averages for a total points league makes sense.
It's much different in a title game though IMO
I can somewhat see that logic. In a one week matchup, a player's potential point range is obviously going to be much wider than, but either way you have to assign a point value whether it's zero or a mean/median/mode.
I'm not a fan of assigning a point value that was never achieved. Not for a title game.
Two scenarios:
A team wins because you assign averages.
A team loses because you either give zeros or the few points guys scored.
Both are unfair, but I think the LESS unfair option is using the few stats accumulated Monday, and basically treating it as though all the Monday players got injured.
It certainly isn't going to be a shock that people will have a bias towards which option they prefer. Pretty sure it's directly related to what benefits them.