I saw Bezos talking about this delivery system on 60 Minutes and I immediately thought it was impractical because of theft and weather. I can image people trying to shoot them down even. Do these things fly well in all types of weather? I didn't think about the apartment number problem. Interesting. Maybe there will be Amazon chimneys on roofs of houses where the drone can deliever without even getting near the ground.
But do we really need stuff in a 1/2 hour? If so, it must be life threatening then and you should probably spend the time getting to the hospital.