This is tangential, but still related: a few years ago I could buy disposable VISA cards which were these vouchers you bought in a store and were preloaded with a fixed amount. They didn't even have to be in your legal name.

I put the numbers on e-crime forums for people to snap up, and it was funny watching what kinds of transactions were being made. Most people were using it to buy cryptocurrency.

Most of the transactions were vague though and didn't mention the merchant in question, but with a bit of digging I discovered they were so called 'Discreet Billing' companies which are largely used for adult websites and used to mask the fact you were buying porn to people casually glancing at your CC statement.