Scan to pay

At the corner of my street, a woman I know as Mrs Bay sells bánh mì from a glass cabinet on the back of a bicycle. Beside the cabinet hangs a laminated square of black and white dots. Ten years ago I would have counted out notes. Now I hold my phone up, wait for a short chime and walk away with breakfast. The whole thing takes four seconds. I have done it so often that the first time I paid cash in a shop abroad, I felt oddly clumsy.

Vietnam's move to QR payments has been quicker than most visitors expect. Banks and wallet apps agreed to use common codes, so a stall owner needs only one printed square to take money from almost anyone. There is no card reader to rent and no machine to charge, and a notification pings the moment a payment lands. For a small trader, the benefits are real. Mrs Bay says she no longer carries large amounts of cash home at night, and she finds it much easier to keep track of what she has earned.

I am not here to complain about any of this. What worries me is who has been left outside the circle. Plenty of older people never owned a smartphone, and some who do are afraid to press the wrong button and see their savings vanish. A retired neighbour told me he now carries a small card with his bank details, which his grandson wrote out in big letters, "in case a shop will not take my notes". Nobody has banned cash, but nobody has made sure it will be accepted either.

Then there is the question of who ends up paying. The transfers themselves are mostly free for the customer, but the businesses behind the apps are not charities. They collect data about what we buy, where and when, and they are learning how to turn that into loans and advertisements. A stall owner may find that the free service of today is the product she is sold tomorrow. None of this is a scandal. It is, however, the kind of slow change that is easy to miss until you are well into it, and much harder to reverse after that.

So what would I like? Nothing dramatic. I would like shops to keep accepting cash, even if few customers use it, and to say so on a sign by the door. I would like banks to teach older customers to use the apps in person rather than by text message. And I would like the rest of us to remember that a system which works for ninety people out of a hundred still leaves the other ten at the counter, holding money nobody wants. Mrs Bay, when I asked, laughed. "Cash is cash," she said. "I will take it from anyone."