The checkmark is obtainable when proof is supplied, that won't change.
It costs $8 a month, for nothing.
it boosts you on the algorithm in replies and shit. you can argue that the checkmark system before was good, but i would be against you on that. $8 a month for more engagement isn't a big deal, and it's being adjusted by the value of currency in your country
Like Critical was going on about, it's a system that tells people the $8 spender is more legitimate. In his case he has no plan over buying the checkmark, so he suspects scammers will be able to use his name as if they were him over their willingness to pay money he otherwise is not.
It doesn't even get rid of ads, it halves them.