Yes it helps - but is only one form of SEO. You have to be careful not to over-do it, though, you'll get tagged for Ping-spam, you'll become the boy who cried, "Ping!"
It's best to use pinging in a mix of other SEO, traffic-getting hub promotionals.
A great way to get traffic is to blog comment, using your hub URL as your website, social bookmark, write an article or 5 and promote your hubs, then RSS your bookmarks, articles and author's profiles (in the article directories and HP) and then ping-mash them at IceRocket or the like - then submit the massive RSS to various RSS aggregators and then ping that.
Hope that wasn't like an avalanche of info...