A ride in an autonomous vehicle should be far less expensive than a ride in a manually driven Uber vehicle.
If the end goal for both is a fleet of autonomous vehicles and a strong app to facilitate the use of that fleet by the public, I would much rather be in Tesla's position. Having a fleet and needing to create an app sounds a lot more promising than having an app but no fleet. Tesla will be able to get an app up and running far sooner than Uber will be able to get a fleet.