I was updating my old high school on OSM and noticed that whoever mapped it before used a multipolygon to map the buildings. From what I can tell the benefit to this is that you can map more complex shapes by having them be related, is that correct?²

There are some buildings that have been added as building=yes instead of building=school (some haven’t been marked at all) and I want to make sure I understand it better before I go and make any big changes.

¹ my old high school for context - Esri World Imagery has the best image quality once you zoom in.
² My understanding comes from this wiki page

EDIT:
Some extra clarification as to why I’m asking. There are some buildings that have been added as separate multipolygons which don’t make sense to me. (see screenshot), these two buildings were added as separate multipolygons but they are connected and form part of the same building.

I also get a warning in JOSM that says “amenity inside amenity - amenity=school inside amenity=school”