The problem with the cloud approach is you're using and storing data and credentials (even temporary) onto an unknown device. I don't think that'll ever become the norm. Using a phone to handle all this means you only need dumb hardware to hook into (which, again, could be accessed wirelessly) so even if the hardware is compromised there are still security controls in your device to limit the damage.

Ultimately I think the final outcome, which may take many decades to get here, is a device embedded inside of people that give them access to everything they need and if they need another way to interact with the information they'll use some sort of dumb terminal (because if everything is embedded in you and can be accessed easily via some wireless protocol, why would you go through the hassle of a separate authentication step where all your data could be exposed).

Whether there is a market for this today or not I don't really know. I'd love to find out but this is the type of thing that would require quite a bit of start-up capital and an MVP might be difficult to do.