Fundamental design flaw
The thing about doors and people is, the people who stand outside the doors tend to be of varying height. So when you combine camera and push-button, you end up seeing a tall visitor's midriff instead of their face - or you put the bell so high that smaller kids can't reach it at all, or if they can, they can't get their face high enough for you to see anything more than a disembodied waving hand.
And given the price. it would probably be cheaper to employ a full-time butler to answer the bloody door in the first place.
Biting the hand that feeds IT
