The photo of the terraced farming actually brings up an interesting point–in order to render those slopes usable for farming, terracing approximates the “flat” projection of the terrain anyways, so you end up with the same result. Buildings and any other usable structures follow the same rule: you can only build vertically, so the effective surface area is the same as the flat projection.
Is that not the normal? I just started sailing again recently, and I legit feel bad having to clear out an old torrent to make room for something new.