A lot of small towns do that. In many residential neighborhoods, like the one I live in, there is a mailbox "kiosk" (for lack of a better word) every block where the mail gets delivered. They look like miniature versions of the wall of boxes you would see in the post office. So rather than having to stop at every house, its one stop per block which saves a lot of time.
I may be wrong, but it seems like one of the costliest parts of the service is the to-the-door delivery model.