Visa and Mastercard allow adult. They just force you to pay the "high-risk" category. Which is much higher fees. OF can't get away with only charging models 20% if credit card processing is taking more than half of that.

I suspect they are currently not classified as adult and the banks are saying, look, you are almost entirely adult so you have to pay us more.

I mean, yeah, that's one of the mechanisms. Charge you close to an order of magnitude more for being "high-risk", while also putting all the actual risk on you as well. Visa/MC are more than compensated for each chargeback with the additional fees the charge the vendor for each chargeback.

And this is typically offset by maintaining a rolling-reserve too. Any merchant doing over 200K in transactions is considered high risk.

It shouldn't matter from Visa/MC's perspective because they put the cost of chargebacks (and more) on OnlyFans.

For some reason payment processors have always viewed themselves as morality police.