Yes, I am sure it is useful, although I was not yet able to discover its effects.
I only started to use it about a month ago. So far I know that my hub about the Chimney Cake (Kürtőskalács) got pinned over and over several times and this brought some extra traffic to that hub, too. Not that much, but it is still a traffic rise and that is always good.
I hope I will be able to report about it more in the future.