What about getting carded for drinks? I don't see liquor store owners, bartenders, and club bouncers accepting digital driving licenses as proof of age any time soon. How would they confirm authenticity?
But I would love this to happen ubiquitously. I also need my insurance card in my phone (since it is legally required here).
Another issue: with all these cards and tickets going digital, we're often going to be forced to hand over our expensive phones with personal information to people. It would be ideal if we NEVER have to hand anything over to anyone because EVERYONE is equipped to accept Apple Watch for EVERYTHING, but that will never happen in this world. Instead, maybe it would be better if we had some sort of cheaper peripheral that we could hand people rather than our phones, like an e-ink card. It could sync with our phone and temporarily display card or ticket information on it. This kind of reverts back to having a card but at least it's only one card. And maybe it can attach to your phone when not in use. Maybe if it's designed together with the phone, it could even serve as a secondary e-ink screen when attached, which can save battery.