Switzerland already have QR code based payment (twint, can debit directly from your credit card). Bunch of self service farm products simply have the qr code.
It's also common to have qr-code or cash only payment available in mountain restaurants.
(or even in other venues, was surprised to have a large festival in Zurich which was mostly qr-code or cash).
So what do yo do when the AZ you are in is down? You use cash. Remember what happened in Hawaii this summer? Don't take anything for granted. It mostly works but what do you do when it doesn't?
When your closest AZ is down, it failovers to the next closest AZ. That's what AZs are for, there is no single "electricity switch" that could get hit by a tornado.
It's also common to have qr-code or cash only payment available in mountain restaurants.
(or even in other venues, was surprised to have a large festival in Zurich which was mostly qr-code or cash).