Activision is making people believe in the weird DS "drum skin" attachment for Band Hero the best way it knows how: by finding the most excitable shills it can in shopping centers, and putting the game in their hands. Predictably, they love it. We've never seen a mall so full of people willing to dance awkwardly to a DS game.
The buttons that go on top of the DS's buttons are only one of the selling points espoused in this trailer. Band Hero's extensive track list and flexible multiplayer (just like in the console version, you can combine instruments in any configuration) get lip service too. But they aren't as noticeable as that thing you put on the DS to play drums.