My main issue with whatever tech is used, is
the speed an order is filled. Pick a card, stick it in slot, wait two seconds, listen for sound tone, door automatically opens, take out your hot/cold food and beverage on a tray. It stretches reality to think that most techs can deliver in that short of time. Turbos and transporters, at least for humans, take much more time to use than one or two seconds, then put the preparation time on top of it, this boggles the mind.

I think the food is already prepared and behind the wall, so, all the system does is move it from a storage rack into the food slot. The menu is restricted to stuff-of-the-meal per the chef. This is how the food is served at my work, today. Example: lunch selection today is roast pork and potatoes. Take it or starve.