I was working with drones for a while and one issue with carrying weight was distance. If you want a drone capable of carrying weight it has to have a specific size to accommodate the heavy object as well as batteries that get heavier the longer you want to fly and the more power you need to transport said object. Outside of that rules about line of sight were a thing, so you couldn’t just let the drone fly a pre-programmed path but you also needed to see it. There is also a risk of being shot down. I think at the end of the day search and rescue or coast guards might use drones to deliver something very quickly if there is no other way but outside of that I see challenges that are rather hard to overcome.