I have to admit, I was intrigued by Passbook when I first heard of it. An app that keeps my airline and movie tickets together with my coupons and customer loyalty cards seems like a good idea. For now, however, Passbook in iOS 6 seems like a placeholder to me, an app with no real purpose in and of itself, a place to link to other apps.
Apple quietly added a little explanation in the form of a paragraph in the iTunes Store page for Passbook apps which shows, at least, that they’re planning on more and that they understand that we all might feel a bit nonplused about one of the bigger features of the new iOS.