A lot of the bigger Adult related sites are looking at other Alt coins like Vice Industry Token (VIT) - See for example what Playboy TV did,
https://www.coindesk.com/playboy-tv-to-accept-crypto-payments-for-exclusive-adult-content/Bitcoin is a much better solution and will even be faster and cheaper than most other Alt coins, once the Lightning Network is fully implemented.
Some people on Tor, like to ask for Monero and Dash for their content, because it is more anonymous than other coins.
Was supposed to mention about VIT(vice industry) and XVG(verge) when it comes to this porn thingy and since we do talk about Bitcoin , just like been said above ive seen some services which do offer live cam shows which is on the payment is on bitcoin or any other payment options.
When it comes to anonymity then i would hands down for Monero. Porn industry is already being utilized here on crypto.
You could just use a clean Bitcoin address which has not been posted anywhere else on the internet by you and do it that way. Monero is not as popular as Bitcoin and there would be no real incentive as a business model to accept it as they are just limiting their profits.
Monero should probably push for this though as it would be a great incentive for people to buy Monero over Bitcoin and other altcoins.
Privacy-focused Cryptocurrencies will face a lot of troubles in the coming years, because government regulations will focus in on these currencies. The complex on-chain cryptographic methods they use, make them more anonymous than Bitcoin and that makes them more suitable for illegal porn.
The problem is governments will push back hard and these currencies will not be used in large industries that are properly regulated.
It is also used in the more illegal side of the porn industry, like Child pornography.