I can't speak for all things, but I found that venues will often use like a rotating QR code or rely on NFC. I'm sure if this is something like a ticket for a concert, you'll just rely on the existing pass support from whatever service you're using because it'll require something more complex.

The way I'm interpreting this is that it's a way to abstract stagnant QR or barcode passes for smaller businesses and libraries. We'll see at the WWDC though.