Worth it to note:
if the walls are thick enough,
Robot arms can be used to create decorations/sculptures/patterns
on the exterior and interior.
'skin' can be applied (paste of materials, for certain aesthetic
and also, protective effect against the weather) once the
decorations are complete.
So that would add, moving parts (gears) complexity to the
buildings in its functionality as well as,
sophistication in design, in its exterior and interior.
Minimizing time to create, while maximizing meaning to the buildings.
All depends on the material used to compress earth.
In order to save costs, possibly an adhesive, a natural type
of 'glue' by agricultural production could be used
instead cement. If cement, manufactured from scratch.
Possibly more simpler in its ingredients, but,
still holding enough structural density to work with the
CNC, and robotic arms.