Guests fiddling with their phones is not QR-dependent from what I experienced.
Also, waiters can be helpful, and friendly even when there's no paper menus. In my current city most restaurants are QR-enabled, and they serve food as nicely (or not) as paper-based. Absolutely the same experience except how you looking into menu. I just stopped noticing the difference.
EDIT: Maybe important note that I'm neither in US, nor an EU country.
Also, waiters can be helpful, and friendly even when there's no paper menus. In my current city most restaurants are QR-enabled, and they serve food as nicely (or not) as paper-based. Absolutely the same experience except how you looking into menu. I just stopped noticing the difference.
EDIT: Maybe important note that I'm neither in US, nor an EU country.