Difference is in fees and licenses. Payment processors that process high risk payments (adult industry, gambling, etc...) have higher fees and need license from governing body (usually a national bank in country where the payment processor is registered). So if you process high risk payments as low risk you will get a fine from governing body and you risk to lose your license. And if you don't have a license for high risk payments you cannot process them.
I don't work there anymore, but I heard they lost SEPA license a couple of years ago because of risky transactions.
Now I am not sure if Visa and Master are forcing payment providers to give up high risk transactions or if they are forcing them to classify all transactions as low/high risk.
It could be through vouchers sold at gas stations, bank transfers, QR payment apps, etc. But CC has by far the best penetration and most alternatives are weak at best.
If you do figure out the alternative payment or distribution strategy immune to pressure through CC, then it changes targets to legal systems and NGOs. You'd want couples of congresspeople or to push back on that front.
The way the policies work, they would either have to use the latter processor for all transactions (which would be prohibitively expensive) or relegate all "adult" content to a completely separate company and domain, which would be a huge pain and expense to operate for something that constitutes a relatively small fraction of their business.