As with any type of motion picture, some viewers want the visual experience, and some want to be told a story.

The thing with porn is that it is a tough call to try to force feed too much of a story to the viewer.

Sex is a personal thing, and like two snowflakes, no two people have the same personal needs for sex. If the producer/story teller tells too much, the viewer can get turned off - or at least taken down the wrong tangent.

Better to let the viewer's imagination run wild, than a Producer going nutz with all sorts of bizarro stuff.