Imagine a few of those things taking off from a self-driving car, doing the delivery, and getting back to it a hundred meters further.
The cars have a problem, that they can't get the products to their final destination.
aircraft carrier for drones brilliant!
I'd be willing to bet we see self driving "moped/scooter" deliveries before self driving car deliveries simply because of the physics / liability implications. If reliable car systems can be developed, scaling down makes a lot of sense. Economically, it would be much easier to insure a moped than a car/truck, IMO.
How does the delivery get from the moped on the street to my front door on the 5th floor? Maybe a Segway type thing would work better, it just needs to be able to press the lift buttons.