I still don't even get what the hell it is or how it even works. No matter where I look I can't get a clear explanation. How the heck do I use it?
There's no way you've looked and not gotten a clear explanation; however, I'll tell you what I see it as. For me, passbook was to replace an app called KeyRing. That is the place where I keep all store cards so I don't have to carry them around in my wallet or on an actual keyring. Where passbook is supposed to prevail is with other things like movie tickets, concert tickets, and plan tickets. The issue though is that there aren't enough people on board with this "tech" to read passbook.
I created a PetsMart card with it using an online passbook card generator and it worked perfectly. I downloaded the Walgreens app and got my passbook rewards card in there so each time i'm near a certain Walgreens (that I designated) I get a popup that tells me I'm nearby or some **** like that.
Passbook isn't what it should be yet but if you really want to see how well it can work then I think the best example you have today short of flying United and using it for a boarding pass, would be to go to Starbucks and use it.
Eventually it can be great unless it dies a sudden death like Ping.