Just curious, how do you actually see this? Maybe:

A self-driving car pulls up and double-parks in front of your building. It texts you to come outside and gives a four-digit pin. You go to the car, type the pin in, and a small door opens with your package sitting there. I guess the car has some weird conveyor system for moving packages into the pickup area.

Is this what you are thinking? I'm not sure how well double-parking by a self-driving car would work (delivery people do it, but they also can use their judgement). The conveyor system also seems like it would create problems.