Drywall vs plaster on masonry

So they would probably be fully glued over the entire surface. Thickness would be about 1.2 cm, so actually nothing.

I also consider this representation to be a misunderstanding. For old building walls (especially those with timber framing) that cannot be satisfactorily made vertical with plaster, this may be the material of choice. But for a solid masonry new build wall, the flatness of the plastered surface is easier to achieve.

The upper floor would be completely drywall.. One would probably have to like that or not ...

In pitched roof upper floors, drywall interior walls are popular with many house providers, while in "city villas" masonry is more common.