Completely understand, I was in the same boat. I have been using Keyring forever and love it. The idea of ditching all your loyalty cards to have them on the phone is definitely the way things are moving - but Passbook isn't that yet.
I think eventually it will get to that point, but it is up to the App developers themselves to redesign their apps to ingetrate with Passbook (something that as of right now only about 6 companies have done)
EVENTUALLY - it should work as demonstrated when Apple showed us the launch video but for right now, it's just a few apps that work with it. All the cool ones we saw (Airlines, Starbucks, etc) are not yet built or active.
My guess is that within a year there will be many more apps working in conjunction with it.