Before, you could go to a restaurant, look at the menu and order: it was as simple as that. Now many places don't even have a physical menu anymore; they assume the customer has a “smart” phone and an internet connection. If this is the case, the customer is expected to use the camera and scan the QR code, which takes them to a web page that does not respect their privacy, often takes a long time to load and, in many cases, is not very intuitive.
It is inefficient, it pollutes more
Loading a web page with images from a remote server, for every customer, is polluting. With a physical menu, no electricity is wasted, people can reuse the menu indefinitely... If there is no Internet or you have no battery, how do you read the menu with the QR?
When we visit a website we leave a digital footprint. If we use a QR codes to consult the menu, there are companies, governments, etc., that can know that we have read the menu of a specific restaurant at a specific time.
Customers also lose their privacy when they pay by card instead of using cash, but that's another issue.
Better without QR-codes
I don't have a “smart” phone and I don't like restaurants. If I eat in a restaurant, I ask for the physical menu. If they don't give it to me, they have to tell me the menu, because I have no way of seeing the QR code. Most restaurant food is unhealthy, the workers are often exploited, a lot of food is wasted, there are few vegan options, and so on. The restaurant industry has many problems. The use of QR codes for menus is just another step in the wrong direction, but it's very easy to combat by refusing to use a “smart” phone to scan a stupid QR code.