Earlier quoted context omitted.
If they're going to the trouble of pre-arranging the ride, why don't they just use cash/Venmo/Square, and keep Uber's cut of the fare?
Yes I wonder what makes this different from the Homejoy situation
The rest of the time, if you need a ride at a time/place that isn't regular, the driver you know might be far away, might not be driving at that time and might be driving someone else, so it will generally be worth it to pay a premium.