> If your new system interacts with the old system at all there is an attack point.

Yes but no. Currently the issue is that these two payment systems - both credit/debit card networks - (1) have the power to decide with impunity, because they have critical mass. And (2) have visibility into who each vendor is and what they are selling. If there is one case of abusing market dominance, this is it - and for all we frequently hear, this is REALLY not all that common. (And it's "funny" that we hear a lot about Apple's app store - but not about their anti-adult content rules!)

For example, right now a bank would have a VERY hard time preventing you from paying for $OBJECTIONABLE_CONTENT with crypto. That bank would have no visibility into who you are paying with that crypto. There are other crypto intermediaries but they are "diffuse". Nobody in there has both visibility and power.

For example, right now some vendors accept gift cards as payment. Buy a Home Depot gift card in cash at your local store and use it to pay for $OBJECTIONABLE_CONTENT. Obviously this is not a very efficient payment infrastructure but it exists.

But yes of course, imposing to credit card networks to be content-blind would be helpful and soooo much more efficient.

The big credit/debit networks can easily justify killing buying crypto.

Terrorism, money laundering, illegal things like drugs, whatever.

If it’s hard enough to get crypto, then it doesn’t matter if it’s technically an option.

You could make it possible to buy this stuff with Fruity Pebbles box tops. They’d have no visibility into that either. And roughly no one would do it.

They just have to make this stuff hard enough. And that’s currently very easy.