Why not? It's free. By definition of the cost vs benefit analysis (I don't have to read a business book to figure that one out), you have everything to gain and nothing to lose.

You will not be known as the "craigslist photographer"...no one cares that much. I can list "maybe" 10 professional photographers in my area...and I meet at least one a month. I remember the good ones...the ones that make an impression...never the bad ones. Only 1 of those 10 advertise on Craigslist...and she's quite good. She doesn't have all the fancy equipment that some of the pros do, but she makes it work with what she has.

But yeah, you're probably not going to get much out of it either. You'll have to deal with a few bargain shoppers, but that'll happen with almost every form of marketting.