They aren't going to do much in the way of actually driving traffic to your shop. Google Sitemap will help you get indexed faster, which theoretically might mean a few more visists sooner, but the difference is negligible.
A lot of people do like them for looking at site data, though. I haven't had a chance to use them yet myself.
A lot of people do like them for looking at site data, though. I haven't had a chance to use them yet myself.