The first innings for Passbook were definitely mishandled. I saw a lot of people on Twitter who assumed it worked like Newsstand, where the app itself lives in Newsstand.
This is different to Passbook. Apps (and websites) produce passes which go into Passbook. For example, you book a movie in the Fandango app, which then places the ticket into Passbook. The ticket and the app are completely independent. You can delete the app; the ticket remains. Delete the ticket, the app continues as normal.
However, I don’t agree wholeheartedly with the view expressed by Lavey-Heaton, though; in particular, the latter sentence. The whole point of Passbook is that you buy a ticket for stuff to happen. When you buy a wallet, it doesn’t come pre-packaged with gift-cards? That is what the Passbook app is emulating — a wallet ready to contain things. That is the metaphor that Apple needed to explain better on first launch.