These are "proof of concept" operations and studies on how to safely integrate drones into the national airspace. There are already a number of drone companies making deliveries in the United States. See: Zipline, Google Wing and DroneUp.

FAA regulations around drone operations, furthermore delivery are complex and evolving. There are a lot of uneducated assumptions in the comments. The FAA grants exemptions, waivers and special permissions to operators on a case by case safety basis and there are electronic systems in place to support this. For example, if you plan to fly within 5 miles of an airport you can file and obtain permission electronically through the LAANC system.

I encourage those looking for more information to review FAA part 107, 135 carrier operations and the public waiver database for more information.

(Source: I've worked and enabled drone delivery operations, many of which, were first of their kind in this space for over 10 years)