Hadn't heard of it yet. A good idea in theory, but in reality the reason Paypal likely avoided it in the first place was fear of litigation (ie, they don't want to get dragged into court as "facilitating" the sale of a weapon used in a crime - people suing manufacturers have already proven that just obeying the law is not enough).
My guess is they'll eventually get sued out of business, but until that day comes it could be a good service.
