Controlled residential ventilation number of ventilation inlets and outlets

I am a bit surprised by the large number of inlets and outlets that are (often) recommended for [Kontrollierte-Wohnraumlüftung]. Almost every room is equipped with one or the other. In some discussions, there is a debate about whether [Kontrollierte-Wohnraumlüftung] is even necessary. I would have thought that two inlets in the bedroom and living room and two outlets in the kitchen and bathroom would be sufficient for a 120 sqm 2-person apartment. Isn't that correct?

Rooms that do not have a valve or are not used as an overflow area are not ventilated. Obviously, it probably makes sense to have the ventilation system ventilate the entire building …