By John D. Sutter, CNN

(CNN) — Phones do everything in South Korea.

On a recent reporting trip to the country, I made a point of asking people about interesting ways they use their smartphones.

Some answers weren’t too shocking. Lots of people know Koreans use their phones to make purchases (that’s a new-ish idea here in the U.S., and one that Google is pushing) and in place of public-transit tickets.

Cab drivers in Seoul give you weird looks if you try to pay with a credit card instead of with a tap of your phone.

But one answer surprised me:

People now use their phones to buy groceries in the subway.

Over the past five months, Tesco, the British chain, has been opening virtual grocery stores in subway stations and bus stops in Seoul. Commuters use their smartphones to scan and purchase these virtual items, which are delivered to their homes.

“It’s really captured people’s imaginations, which is something that’s really magical in retail,” said Roberto Munoz, a spokesman for the company, which goes by the name Homeplus in Korea. “It has people thinking outside of the box about how they can purchase things – and the convenience with which they can purchase things.”

The subway station walls look just like the shelves of a typical grocery store – only the items are just photographs and each is tagged with a QR Code (those black-and-white checkered things). Shoppers launch a Homeplus app and then scan the QR Codes of the items they’d like to purchase. Money is automatically deducted from the bank account of their choice, and the groc