There are intelligent people who swear. A lot. Some very funny people who swear too. But as one who has definitely relied too much on swearing to make things funny, I think wit is lost when the entire brunt of a joke depends on whether you use a vulgar (literally common) term or not. It's too easy and anyone can do it. Not swearing does cause you to be creative and I think it's more rewarding to expand your vocabulary and reflect some on the art of comedy.

*stands tall and proud* =D

*is chased off by a mob of expletives*