Needless to say, I gave the driver the key, R. paid him on the other end (with a sizable tip) and everyone was happy.
I also know a bunch of people who have rolled their own delivery service for restaurant takeout by using a taxi to go get the food for them.
As near as I can tell, Uber's main addition is the app, ability to track, and name recognition.
I like to think of this as, why the hell should I have to go there to get that, why can't it just come to me? -- one of my major life themes.
ETA: Uber is not silly; they are well aware of this and realize they are marketing and organizing something that people are already doing with their existing service.