AFAIK they are intended to be quieter, cheaper, and safer. The same story as electric vehicles - fewer moving parts means lower maintenance costs, but particularly important when talking about air vehicles is that it also means fewer things which can break during flight. Helicopters are nasty dangerous, largely because they’re maintenance heavy and there’s little redundancy. “Drones” could address both of these.

Also much easier to fly I imagine.

The Uber Elevate white paper probably has a lot more info: https://www.uber.com/elevate.pdf/