When a recruiter calls someone out of the blue, the response from the recipient not always friendly. "Oh he's just another telemarketer," is their attitude. But is that really true? Why is the recruiter calling? To tell you about a job that might be good for you. And what is he charging you for a chance to see it? Nothing.
Even when people are polite, the reflexive reply is often, "I'm happy where I am." Well, of course you are. But what if you had the opportunity to look at a position that might be an improvement on what you have now? Is it that impossible? And what would it take to find out? A meeting with the recruiter's client?
Even if went nowhere you might you learn something worthwhile. It would certainly keep you from getting stale in your own personal marketing which is a real hazard. Many people find that when they want to look for a new job (or have to) they don't know the first thing about doing so. They're lost and have to struggle to get up to speed when the pressure is on.
And, you know what? It doesn't really matter if you don't like the recruiter or if you think she doesn't know much about your profession. If she can get you into an interview for a position that could be worth looking at, that's all she has to be able to do to make her someone worth speaking to.