Durability of this 3D printed houses would be a challenge as the soil in all the regions varies- so it is just going to construct MUD houses, not solving the housing scenario of 3rd world.

Where as acceptablity from the local would be a challange. most of the third world is facing problem of high population and unemployment- specially of unskilled nature.

Future looks great with 3D/4D tech, but will be accepted in market as a sudden change???