I snapped this photo making a sales call at a home out in Deep Cove. I was trying to get the builder to order a few of my ACO linear Drains and while there priced the work to build the showers. This was going to be a steam shower.
If you look close in the photo you can see wood blocking between all the wall studs. The original bottom plate covered by a 1.5" concrete pour which encapsulates the heating pipes. If the drywall did not go to the bottom there would be no support there for the bottom of the wall. Drywall plays a huge role in the strength of a wall and structural engineers even specify the nailing or screw pattern on their drawings.
This is a photo from a bathroom build in the USA that I'm helping with the steam shower design. When concrete board is used it requires added blocking - I shaded this photo with some blue bands to show my client what she should be asking for from her framers for this step. My local BC Building code does not require this added blocking. The Canadian Building code does not - it is the cement board manufacture that wants to see it.