My home address is of the form m Rivendell Lane, #n. Rivendell Lane (name changed) is a condo with multiple buildings; each building contains multiple dwellings, each with an outside door. When tradesmen come calling, most of the time their dispatcher omits the unit number n, and they go knock at the door of unit m, which happens also to be in building m. They then call their dispatcher, who calls me; I roll my eyes and explain. Without mobile telephones I’d never get anything delivered!
I can’t think of any functionality that would be lost if the buildings as such had never been given numbers. My address would then be slightly shorter and free of ambiguity.