Strapping your card to your phone in one of those magnetic card wallets seems to achieve the same level of convenience, or close, and avoids all of the downsides of running a Googled system.

I personally find using a plastic card more convenient than fumbling for my phone and unlocking it (I don't use biometric unlocking as it's not protected by the 5th.) It's also easier to go somewhere without a phone (yes, it's possible) when you have a card on hand.