I assume because as soon as you become the "place where people get crypto for adult content" then the same issues that OF is running into now become your issues as well.
Unless people are getting paid directly in crypto, they are purchasing it from somewhere, and wherever that entry point is will have this problem.
Yes, already now buying cryptos is ridiculously difficult. Any reputable operator requires KYC, which is a similar process to opening a bank account including submitting a photo ID. That's a pretty good deterrent for the random Joe against signing up on a porn site even if it's all legal.
While cryptos in of themselves are decentralized and inherently unregulatable, people forget that the interface with the real financial world is very much vulnerable.
True, but there are services like Purse.io which let you order on Amazon and pay with crypto. So theoretically, you could have your fans pay you in crypto, and you could convert that to whatever goods you want. It might not work as your only income, but could be a valuable way to supplement it.
Unless people are getting paid directly in crypto, they are purchasing it from somewhere, and wherever that entry point is will have this problem.