It's not wasteful because Interior Mapping replaces many objects (which would each have their own vertices and textures) by a single square and texture, so you

It's not wasteful because Interior Mapping replaces many objects (which would each have their own vertices and textures) by a single square and texture, so you can have a complex room with many objects at the cost of a single object. Example: https://andrewgotow.com/2018/09/09/interior-mapping-part-2/ https://andrewgotow.com/2018/09/09/interior-mapping-part-2/