Adult content usually has a high charge back rate. “What? How did this get here? My card must’ve been stolen” when the spouse sees the statement.
https://directpaynet.com/new-visa-rules-dating-adult-info-pr...
So I could see why issuing banks may not want to support adult content, but then there could be a porn friendly issuing bank that may charge higher fees or something.
but they do work for most non-recurring type things akaik.
I have seen people have them fail - because they quickly try to use them, not knowing that many places require at a zip code to be entered that matches the card.. and if you have not logged into the pre-paid-card's portal and set a zip code.. well fail it will.