It's not just that rides are a commodity, they also have an immediacy effect. I don't care who drives me, but I care that they pick me up in the next 3 or 4 minutes. When an uber driver gives me a card that's great, but it's kind of worthless because they're unlikely to be nearby. Hell in the time it takes me to call them I can likely have another car at my front door if I just use the app.
Depends. I like being able to schedule rides to the airport in advance, so I know exactly when I'm going to be picked up. And the rate will be pre-determined.
The only situation where it's nice to have a known driver is when you are scheduling a ride in advance, i.e. to the airport or something. In those cases, I frequently call a day ahead to a driver I know.