I would also think it would put off any would be preachers. Simply saying that you are a Satanist would conjure all sorts of images, and they would turn heel and run!
That actually happened to me once in the field service when I was a kid. We approached this guy who was putting a red bible-looking thing in his trunk. He said, "I'm sorry, we're not interested. We serve Satan."
He was very pleasant about it. It didn't strike me for several years that he may have been trying to be ironic.