

my guess is that a lot of people let the game idle in the background to farm items, that’s why it’s so “popular”. It’s not “active players”, it’s just a large number of people farming items in the hopes to get one they can sell for a larger sum.
Afaik it has been in the top charts for over a year.
I can’t find any info about a blanket ban on idle/clicker games, and quite frankly, I don’t see why valve would ban them.
For them, it’s free money: