Simply having to tag two objects given that the building typically already exists. Note that I’m not claiming that this should be universal policy, just that in Switzerland given what data we have available it would seem to make sense.
In any case the problematic cases are not residential buildings it literally doesn’t matter outside of potentially getting slightly better routing, they are the ones with POIs.
My point there was more that while tagging the address on the building and adding entrance nodes work for the POIs in a building with a single address case, it falls flat on its face for everything else regardless of entrance tagging or not. I could bore everybody with tons of examples, but here is just one OpenStreetMap
And just eyeballing it there, it would seem that there is an order of magnitude more POIs in multi-address buildings than the simple case. So should we simply lay down a rule (I know very funny in an OSM context) that POIs in multi-address buildings need to have addresses? Or what would you propose?