T99
3
I think landuse=residential is still appropriate.
Sometimes it’s hard to see the forest for the trees, even for humans. It’s even harder for automata. If a software application is looking for landuse=residential specifically, it will blissfully ignore any and all houses.
Also consider the endless varieties of maps that can be rendered based on OSM data. Oftentimes, particularly at lower zoom levels, individual buildings are not rendered at all. The whole neighborhood could disappear from the map unless a landuse=residential area is also tagged.
Finally, there could be attributes that apply to the area as a whole (rather than individual buildings), such as the development/subdivision/neighborhood name. Such attributes ought to be attached to a closed way that also has the landuse=residential tag.