The commonest failure of a digital menu is not design. It is drift: the printed menu changed, the till changed, and the QR page still advertises a dish the kitchen stopped making in March.
There is one catalogue. The guest-facing menu, the waiter's till and the kitchen's ticket all read the same items, the same prices and the same availability, so a change is made once. Marking an item unavailable takes it off the guest page immediately.
Guest-facing content can carry more than the till needs — a description, a photograph, allergen data, a translation per language — without forking the record that the kitchen and the accounts depend on.
The practical test is whether anyone on your team maintains a second list. If they do, the menus will disagree, and the one the guest reads is the one that will be wrong in public.