It can be anonymous for new users of porn.
As already mentioned in this thread many times, porn users can't remain anonymous. You have to show that you are above the age of 18, to get subscription to these websites. If you are using an anonymous payment option such as Bitcoin, you might need to give some other identification, such as your social security number.
in fact all porn websites use PSPs to process the payments, so the statement will looks like "onlinebilling" or something anyway
but with bitcoins there will not be even this "onlinebiling" in "statement" of course))))