I expect that, if this becomes the norm, you're basically in a world of hurt if your phone gets stolen, lost, broken, etc. Bad things obviously can already happen if your backpack gets lifted etc. But I'm personally already very nervous about tying everything to my phone. I do still carry a wallet, albeit a small front-pocket one with just a little cash and some important cards.

But, then, I don't really like not to have a paper map of some sort when hiking in unfamiliar locations either.