Yes they yield fruit. At least in my area they do. I even ran across a blog where some guys in my area picked them up off the ground in a park and ate them. I can not say if they will yield fruit other places, but I keep reading that they do well in the San Francisco area, the area I live in. Still we may never know about other places if people don't try. It will take some time but if they don't mind I don't either.
Link to the blog
An Edible Palm Tasting Fire Flower