I don't mind favourites without comments, then at least I know they are sorta advertising my art via their gallery. Plus, like you said, no art feedback when it comes to FA.
Plus, I don't get to know people as much there. I have a shitload of people watching me on FA but... I dunno, I think only 10 or 15 of them actually left a comment of some sort. 5 of them regularily come back.
Anywho yes, the demon is expensive but it does pay for itself in the end.