Here it clearly depends on where the delivery service waits after it has pressed the bell. In many cases, single-family houses have 1-3 steps in front of the entrance door (high floor) and there the 1.20m is enough to see the head of the visitor. If you don't have a big floor mat and a step in front of your house, it can cause them to see only the torso of the visitors. If the camera is pointing towards the street, the motion detection would send the first photo with "head" and when you speak, you would only see the belly. Of course, an electrician can simply hang the bell higher but many customers opt for the camera package.