pgt: for me personally i sometimes lack the time to play all games, or joined too many games without realizing (like now) ... i then try to play the games first of which i know that i am holding up things
(i know about 100 games is perfect for me, but somehow i ended up with 300+ games)

i currently make sure that i wont timeout, and try to make sure that i have at least 2 days left when i sign off, and when i have more time i try to make a move in as many as possible

a way to put those games to the top might speed up those games which require faster play

without a way to favourize them, i just play according to the 'time left' table ... which might turn out worse for specific tournaments

with a way to make some games favourite, my opponents can ask me to speed things up, and its easier for me to help them

especially for those tourmants that we want to finish faster, its a nice way which might speeds things up

without favourites, things stay like they are right now
with favourites it might improve (slightly)
i dont think favourites will make those slow players play even slower, as they seem to pay no sp[ecial attention to it yet, but maybe with favourites they might pay attention ?

of course it still depends on the players though :)