So, there actually is a reason to do this beyond pay, but clearly pay is the actual reason they do it.
A restaurant has a set amount of staff. What happens if a few are sick and they have trouble finding someone to fill in?
A remote agent like this could be from a larger organization being contracted out and you’d never have to worry about not having someone to be available.
Edit: 1 person could even be managing multiple stores where they queue the person to assist you as it detects you approaching. Less ideal would be ‘someone will be available in 45 seconds’ type queuing.