My first thought is that it still requires them to follow up on catching spammers (similar to the paid checkmark, this as a “solution” makes me think they won’t do that).

I could see spammers deciding “hey, I’ll make more than $1 before I’m caught” and do something with payment to hide their tracks (maybe a simple thing that should be known), meanwhile normal users say “Eh, I gotta pay? No thanks.”