I looked into building an earthship in my area and was shot down pretty fast. But also, I wonder if Terlingua and other places in the US don't have codes for the same reason some countries don't have them- corruption. The recent disaster along the border of Turkey & Syria is the dark side of no building standards.
It's not at all to my taste, but that house is probably sturdier and more fire resistant than 99% of the modern "lightweight construction" houses built in the last 30 years.