The QR code is physically attached to the table and links directly to the menu and/or your bill. QR codes are cheap (any printer can print one) so don't need special equipment. And people already understand how to use QR codes: they might not understand what an NFC tag/beacon is, or it might not work with all devices.

What would NFC add that you can't do with a QR code?

(Use of a QR code doesn't preclude paying in the normal way by calling over a server and using a contactless payment terminal. It just gives you the option to skip that and pay directly from your device.)