Air Canada has the same thing. There are no direct benefits (that I know of) for the flyer. Hopefully, it does help to improve the level of service over time. I save them for truly monumental efforts (e.g. getting me on an oversold flight at the last minute) or for flight attendants that are having fun with their jobs (I was kept in stitches by one from Houston to Toronto in June--he told several good joke -- in addition to paying attention to detail, being professional etc., was obviously having fun on the job).