I don't. I tend to just scroll right past them. I agree with what was said above, that they often have nothing to do with what was searched.
But, with that firmly in mind, I'm still, considering, just out of curiosity, running an ad for a couple of dollars just to see what happens. Being found in the jewelry market is tough work, and I often feel like I'd try anything to be seen and make a sale. Obviously, people must click on the sponsered ads, or they wouldn't be there. Right?
So there's my take on it. There are two sides to this coin. Time will tell which side is shinier.