This is actually nothing new. Most electronics locks have had this capability for a very long time already. I've given service people their own pins, that would only work on certain days during certain hours. I've given my friends, my former roommates, and my family their own pins so they could get in whenever they wanted. The system keeps a pretty comprehensive audit trail of who comes in, so if someone gives their pin to someone else, it's usually pretty easy to figure out.
The only difference between that system and the lock I use is that this system is internet-enabled and accessible through a phone app, but then again, I haven't upgraded that lock in the last fifteen years, so such a change is to be expected. Also, there is the cost issue. These systems are not cheap. And this one being advertised slyly on Slashdot isn't cheap either.
As to the postal worker or the UPS guy, I've never given them a pin. Would they even take it if I gave it to them? I doubt it (unless I was really on very good terms with them). Even accepting the pin to a garage can lead to potential problems. What happens if I start to claim that valuable things have started missing from my garage on the day of deliveries? What happens if there is a dog in a garage that comes out when they open it? Do they run after it to put it back in there? What happens if there is a dog that comes out to bite the uniformed intruder? My UPS guy can handle dogs. He gives them little treats (with my permission of course). So my dogs start to salivate when they hear the UPS truck pull in, or see someone in a brown uniform. But my postal delivery man is still completely clueless, with his little pepper spray bottle. My dogs don't like him, or anyone else wearing a blue uniform.
When I lived in the inner city in a small apartment building, I recall the postal worker having a master key to my outer gate, so that he could access the mailboxes, but that's about it. Being able to open an outer gate is not the same thing as being able to open a garage (whether that large garage door is automated, or manual). And last I checked, city services are only decreasing these days, not increasing. Before the garbage man was willing to open my gate, open the enclosure to my garbage bins, and carry the garbage all the way to his garbage truck. These days, I have to take the garbage out to the curb myself, and the garbage man just leaves the empty garbage can near the middle of the road potentially blocking traffic.