One difference between an adult film and a more mainstream one, aside from the sex, is that directors are a lot more hands-on when it comes to the filmmaking process, sometimes securing locations, ensuring lighting is correct, picking up the food for the craft services table and sometimes even acting as the film's cameraperson. While the production values typically aren't on the same level as a Hollywood film and the writing is generally skipped via the fast forward button, they're still roles that need to be filled.
It takes more than performers on screen to make an adult film, of course.
