oh right those doors and supporting materials (so it does not collapse) can be from earth.

then maybe worth it. (underground)

 

it could be a upgrade to the 2nd photo.

if say the second photo's cylinder can be dismantled in rings

and brought down to be installed into the hollow space of the

underground cylinder,  and added rods to it for support.

 

transformative dwelling as an upgrade.

 

if worth it, is the question.