Another hidden benefit that they may or may not make use of - Apple can directly observe their users interfacing with their products. With websites and to a certain extent with software, usability data collection is a given. But for consumer products like iPods, iPhones and Macs, it's a little harder to come by. By having thousands of end users in dozens of stores around the world playing with their gear, it seems like a great opportunity for Apple to get direct feedback on user pain points.