When I had my photo studio in Basel, Switzerland - incredibly long time ago - sometimes I worked with some models from an agency in the Netherlands.
As you maybe know, my main task in my studio was taking artistic, sometimes very erotic nudes from and for private female clients. Those images were thought simply for them selves, or sometimes as a present for their partner.
Although I had many extremely beautiful clients, discretion, of course, was very important and I couldn't show the results to anybody. Photos were taken on film (digital didn't exist) with analog cameras (those here with a Mamya RB 67, it was before I could buy my beloved Hasselblad), that I developed myself and were then printed in my own darkroom on photographic paper in the normal chemical process.
So the main purpose of hiring models was to produce sample images for my publicity and to hang them as posters in my shop, to have samples to show to future clients.
During the session with this lovely young woman it turned out that she had, let's say it like this: a very open mind full of lust for adventures. It was obvious that she was more than prepared for something that would go far further than simply taking some nice nudes.
Well, I took my Sony video camera and the tripod and visited her in her hotel room, where I filmed her. I had some ideas, like doing a sexy striptease, playing with herself in the shower, caressing herself... and we began using those "stories", but then the thing turned away from acting into real excitement.
When DVD's came up I copied the tape to DVD and sold that video via small ads many thousand times in Switzerland. Remember: there was no internet and such things haven't been available everywhere. There were porn videos, of course, but (almost) nothing that showed a real women in real excitement.
So my video was a full success. Apart of the journey, the hotel and stay costs and a normal fee, that time I additionally paid 10% of the sales to the model. During the following two years she got a check every moth and she for sure was paid at least ten times better than any porn star of that time. Well, I was happy with my part, too...