You're basically talking about the "fast casual" dining craze. Like a panera, where you can order and take payment online, or from a tablet there, and they drop the food off when it's ready. Drinks and everything else until you leave are self service.
Pei-wei is another example. These are all the rage because of the efficiency (less wait staff) but still good food and a sit down environment.
The distinction is in expectation. Certain places you expect a waiter, to be seated, brought everything ("fine dining"). The difference between casual dining is mostly the atmosphere (usually better furniture, tablecloth, cutlery, etc) and a waiter (who may or may not be formally dressed).
The fancy waiter is adding value in the second case, because you're looking for that fine dining atmosphere. If it wasn't, they'd probably be going toward iPads too. Instead they have dress codes.
The difference is the waiter doesn't add much to an everyday meal. The waiter could be terrible though. So in terms of a business cost, that's something casual places can skimp on. For a more "fine dining" feel, you need great waitstaff, so that's harder to automate.