At the keynote address at Apple's tech festthis week, Passbook was shown accessing a whole host of apps. How complete it will be when iOS 6 is finally launched in a few months' time will depend on whether or not developers adopt it for their apps.
Take the Starbucks app, for instance. It currently has a dedicated section within it for your card, which you can use to pay for drinks and check your balance. If this, along with all of your other store cards, were kept in one easy-to-access app on your home screen, it would save you a lot of time swiping between screens and tapping on folders.
What's more, Passbook is integrated with the lock screen so if you pass a cinema, you'll be alerted by a pop-up message telling you that a ticket or reward card can be redeemed. There's also a nifty virtual shredder for when you're done with your card or voucher.
If you're taking a flight, Passbook will also be able to give you additional information, such as the gate number that you need to go to in the departure lounge, which seat you have been allocated and when the flight departs.
Again, this is dependent on third-party app developers making sure that their service works with Passbook, so don't expect all airlines to be available straight away. The British Airwaysapp already allows you to check in using your phone, so it's a pretty good bet that we'll be seeing it on Passbook in time for the launch.
If enough third parties enable Passbook for their app, it will make for a fantastic experience, as everything you need for an event or a shopping trip will be right there waiting for you.
What do you make of Passbook? Do you think it's a clever addition to iOS 6? Let me know in the comments or on Facebook.