[dplavery92]

They became very popular during the pandemic for restaurants to offer their menu as a scannable QR code instead of distributing and sanitizing hand-held paper menus. I think this is becoming less relevant now.

They're popular for street-level advertisements for (concerts, events, clubs, jobs) to provide a link to more information without the consumer having to type a url into the browser. This is more important if you don't want to pay for a pithy high-level domain as a landing page for the thing you are advertising.

I have also seen them for easily entering WiFi credentials to your device on a new network.

They can be used in museums to link to self-guided tour information on the artwork/exhibits you are looking at. This used to be done more with rentable/loanable walkman+headset kind of devices, but makes more sense to do on one's own mobile device now.