As some of the folks here know, I used to work for a porn site. For a brief time we tried this idea out. It was a bit of a failure, partly because we did it on eBay and it got shut down very quickly, and partly because it wasn’t a money-spinner and we didn’t need to, we were doing okay with regular site subscriptions. Also, for those of us involved in setting it up, it wasn’t our kink, so I don’t think we did it right.
We all have our peculiarities. As long as they don’t hurt anyone*, I don’t see the harm.
*Obviously some kinks are all about pain, and even though those are consensual, those are the ones that I find the weirdest, if I’m honest. But to each their own.
The internet has forever changed the meaning of “fairly common”.
Isn’t that always the way it goes, though? Dynamic, young entrepreneurs identify a emerging opportunity, and some of them will build on that experience to be the established players when the market is saturated.