They say in the movie that while they can fake anything, people want reality. It's more thrilling/kinky/disturbing that way, knowing you're using a living person to screw/kill rather than just a computer sprite.Yeah, it really makes no sense for people to sell control of their bodies like that, when you could more easily have an actual video game where the possibilities are endless. You could control a Milo-bot, or be a fifty-foot-tall Godzilla-bot. This is not a movie you should look at too closely. Just enjoy the pretty graphics and mindless violence!