I'm not sure why this is surprising. QR codes are not just a real pain for customers, they put an intermediary between the customer and the establishment. Keeping the customer at arm's length like that would be expected to reduce customer "loyalty" because it reduces the direct interaction with the business, thus diminishing the relationship.<p>Worse are those restaurants that don't even let you order except through an app, even when you're sitting in the place.
Imagine if instead of a traditional menu the server handed you a tiny book with pages the size of index cards (phone screen size...). That could be part of some kind of comedy sketch. This research study shouldn't have been necessary to state the obvious, but I really hope it gets shared around and helps influence the restaurant industry away from the QR codes.