It's a power thing for a lot of those types of people. They know they can just pay for elite level pornstars and do whatever they want to them if they want, but doing whatever they want to their employees and trying to get away with it feeds into the power play angle for them.
I mean, look at Vince. Dude spent like 15 million bribing women so he could do nasty stuff with them. He could have spent like 50k and had way way hotter chicks who are actually into kinky stuff and do it for a job. There's literally fetish clubs he could have gotten girls from.
Instead, he wanted to pay 3 million to poop on some 7-8 that worked for him, not because he had no other choice, but because she was under him and part of the fantasy was seeing how he could get away with it.