Once you get over the feeling that you are living the Tele-Tubby lifestyle, it should be pretty nice.
A lot people use the 10ft high containers instead of the 8ft high so you don’t feel so closed in and fuse anywhere from 3 to 5 or even more together side by side and gut them replacing the walls with new walls laid out just like a regular house.
Even with earth covered there are still windows and a lot of times the windows will have rolling metal shutters in case of tornadoes.
I’ve never been in one but a friend of mine has and he said you couldn’t tell the difference between it and a regular house except they are quitter.
The 10ft ceilings were a lot different feeling than his 8ft ceiling apartment he was living in, a lot more open than your average apt or house.