We also do not have a central ventilation system. Actually, we have clean air. However, I can imagine that on busy streets with a lot of noise and dirt, it can indeed be quite useful.
That is of course an argument. I have now seen this at my friend’s place. He lives on a very busy street. There is a lot of dirt here and also a lot of noise. He cannot just throw open the window, that makes no sense. A controlled residential ventilation system has some advantages here and he uses it.