You're talking about the commercial parcel lockers — the ones that fit a whole neighbourhood's deliveries, that are therefore essentially big sturdy metal storage racks underneath — too big and heavy to just pick up and walk away with.
Every country has these to some degree; I imagine they're most popular in places that 1. have colder climates, but 2. where people don't tend to drive (like Poland?) The US has some, but the suburban long-distance-commute car culture + generally not-too-bad climate, means that people in the US generally expect to pick up packages from further away, and so implementation of these in the US has lagged behind other countries.
However, my comment, and the one it was replying to, are talking about something else — a hypothetical concept of small lockers that serve single homes, given to the homeowner, to be located near the home's mailbox/mailslot. (Basically, logistics-provider-provided versions of these things that you can technically buy online — but where I've never seen anyone with one: https://www.amazon.ca/WeHere-Package-Delivery-Anti-Theft-Pas...).
And the thing about these is... they really aren't a good idea. They're not too big and heavy to just steal. Anyone who can walk up to your porch with a moving dolly can walk away with it.
