My favorite version of this is robotic and drone-based package delivery. In many ways it could be useful and add efficiency to a congested system. But then you find out just what it is that delivery people actually do, the variety of security systems, steps and walkways, exceptions to rules, and so on and realize that what drones and robots automate is not really "the job" at all.
The last mile, in logistics, hospitality, retail or elsewhere is not just a mile, it's an interdependent series of several distances each with its own rules and restrictions. Tech-based solutions tend to solve an idealized, abstracted version of these and end up being only a very limited solution if they solve anything at all.