Ordering off DoorDash seems to me like the worst possible case for agents (or Alexa voice speakers before them.)
I need to see the full menu, with prices and picture of the food and options. Having an agent in the middle is just going to slow me down.
I think the proposition only works if you consistently order the same items from the same restaurant (and so on). It makes the order more predictable ("hey siri, order the same takeout I got from X chinese spot last week").
I don't need to see a menu, prices, or options for that unless I want to deviate from it.
I suppose there is levels to all of these things. For somebody who uses apps to obtain most of their food, this is probably the next step.
Ordering off of DoorDash (or whatever equivalent app elsewhere) in general seems to be the worst possible way to acquire and eat food, in my personal opinion.
Everything on these apps is nutrition-zero junk, filled with salt, oil and sugar, charged at a premium. I ate it in the past, and nowadays I couldn't be paid to eat it. Self-cooked meals beat them in every way, including convenience.