If the walls are hollow it would allow the roots to enter the ground which would in turn help anchor the house to the ground removing the need for foundations and depending on location sure up the land to stop erosion and landslides. This could also act as insulation for cold climates.
If the walls are hollow it would allow the roots to enter the ground which would in turn help anchor the house to the ground removing the need for foundations and depending on location sure up the land to stop erosion and landslides. This could also act as insulation for cold climates.