Problem with such is that these porn maniac don't want to reveal themselves and their identity. There are so many people watching over them including the authorities and they are the usual clients when it comes to child pornography and so forth. Thus maybe they can resort to Crypto as an option.
Well with those vision those retarded person, insane will hide under crypto and watch those content, being with crypto or fiat, the difference is the police wont be able to put them into the prison, but in general is good, some people addicted to watch porn and used credit cards, removing those from the bill would be amazing for them.