1. Why an app would sink the project
Consider what you're asking of a hungry guest, sitting at your table, at lunchtime. Installing an app means: open an app store, sign in to an account, wait for a download on the restaurant's signal, grant permissions, create an account.
At every step, some guests stop. For someone visiting once, the app will never pay for itself — not for them, not for you. And meanwhile they're occupying a table that could already have ordered.
That's the underlying reason, not a technical preference: the browser is already there, already updated, already familiar.