In my experience I wouldn't say they were complete crap or didn't care at all, but I'd agree with the notion that they're a poor indicator by themselves.
When my team would look at candidates, past accomplishments and projects counted for tons more than a cert. Still, a cert told us what someone was interested in and what they wanted to bone up on. They could expect questions relating to that cert field during the call. If they had trouble talking on the subject, then we knew that the cert was likely there to be a pad or just something to fulfill some billet requirement. In good cases we'd find that the cert was an indicator of something they were passionate about.
So I consider it a pointer of sorts. Never worthy of hiring someone on it's own, but I'd recommend them to people who are /ready/ to demonstrate knowledge and may not necessarily have the project experience otherwise. I'd just recommend to them that they be ready to talk to it in an interview.