I inherited an electrical one from the previous owner. It ran on... battery. (Why would anyone do this is beyond me, but it turns out to be very common where I live.) The battery died and I needed a replacement. If I wanted to replace it with something that connects to the power cables inside the house, I'd need to drill a hole in the front wall (made of brick and mortar) and find the closest cable to connect to... And I was too lazy to do that.
On the street I live, there are mostly old houses. Some of them have a bell that exposes a handle on the outside that you need to pull in order to ring the bell inside the house. Some have a "door hammer" (is it what it's called?), a decorative, usually shaped as a ring in an animal's mouth, hammer that's attached to the middle of the door one would use to knock on a metal plate used for this attachment.
I bought an actual cast iron bell and attached it near the door above the mailbox.
What happened is that people seem to doubt so much the functionality of an obvious bell that they prefer knocking on the door to pulling the thread attached to the bell. That's what most package delivery service people do.