Passbook is a solution looking for a problem.
Any app that Passbook makes you download first can just be easily used as well.
Why use Passbook for a Starbucks gift card? I can just use the Starbucks app.
Why use Passbook for flight info when I can just use the airline's app?
Oh, but you'll say, that Passbook puts everything in one place and pops up info when you're in a certain area and is accessible from the lock screen. Well, apps should be able to do that in the first place, but in Apple's walled garden, that's not going to happen.
1) Perhaps, but I bought 2 movie tickets using Fandango, an updated app that lists Passbook integration as one of it's features, and you what happened? Nothing went to Passbook. I still had to show the movie cashier my credit card for him to pull the tickets anyway.
2) I've got a Target coupon loaded. The cashier couldn't scan it from my phone. Furthermore, the coupon seem to be only good at my "home" location by my house, not just any Target. So how is that convenient for me?
3) In order to get things to Passbook, I needed to download more apps that I'd never used before AND I had to register accounts with them. Target, Starbuck, Fandango, etc. Fandango is ok as I've been meaning to make an account with them anyway, but still, it's more accounts I need to keep up with. To top it off, I have to keep checking the apps or else it won't update! Again, not convenient. I'm a registered account, so you should be pushing deals to me via the app and sending it to Passbook automatically. I shouldn't have to load a gillion apps to do that.
But it's no loss right now. Apple launched a product with no support. Sure their graphic looks nice in the marketing presentation, but it's certainly not feasible. I can't see the average person having coupons, movie tickets, airline tickets, Starbucks cards, etc. loaded to Passbook all the time. Someone at Apple dropped the ball severely on this one. I think Forstall knew it wasn't ready, but of course, Apple is silent on the situation. Passbook is now on the back page with the rest of the Apple apps I can't delete.
With me not being able to upgrade to iPhone 5 this time around (thanks AT&T for changing your upgrade policies), AT&T's weak LTE network, and Apple's latest stance on shipping products that aren't finished (Passbook, iTunes Match, Maps, Siri, etc), it may be time to look at Google and Verizon.