It reminds me of the early days of Uber - the value add over taxis wasn’t in the ride itself*, it was the app and the fact that a car would actually show up. I suspect DoorDash et al are similar - the value add is the restaurant selection and the app ordering, not the actual delivery.

(* yes, yes, I too have stories about taxis. I now have stories about Uber drivers, too.)

Yes. Though at least in my market, that used to have delivery fees or minimum orders that made it unlikely you would order a single sandwich for lunch and have it delivered. The food delivery app services really emphasize that model of consumption but I'm not sure it's viable.