That wouldn’t fix the Visa/Mastercard chokepoint, as you need fiat money to buy cryptocurrencies.
But cutting off Bitcoin or other major coin purchasing would have a big impact beyond OnlyFans. Not that you’re wrong, it’s just that the credit card processors would sort of be declaring war on crypto.
Maybe it could move the center of gravity from Visa/Mc. But it is only an hypothesis.
The idea is that with widespread adoption of crypto, there is less need of a fiat onramp since people can get paid + buy things in crypto and not need to swap to fiat.
But you can always just to bank transfer to buy crypto instead of having to go through these payment networks