Follower counts aren't accurate. It's a legitimate broken feature that can't be fixed.
Discussion
They are not entirely useless.
For example; if I hit download follower count on a third party profile, damus shows me people that I know who follow this profile.
Ah okay... Follower lists is sometimes useful to see whether mutual followers are there for some users.
I think follower counts are sometimes useful figure out impersonation accounts, even if they're not accurate
clients can implement mutual followers at the top still. many do this and call it Web of Trust or visual WoT, or mutual followers. i agree that this is useful.