I used to think I was fine with tiny living, because my entire childhood home was 20 sqr meters, but I now live alone in such a space and it's too small. I have huge windows, but the walls are closing in. The space is too small to furnish in a way which wouldn't hinder an aspect of everyday life. I'm so tired of algorithm trying to convince me tiny living is fine when it shows even worse conditions than mine. I wish I lived in 30 sqr meters or so. 40 sqr meters are way too burgoise for me, but I could use extra 10 sqr meters solely for the purpose of farting.
The smart thing with shipping containers is that they're easy to move so it would make sense to use them for temporary housing, like if you're renovating a housing block or if you need a somewhere to house the visitors for a huge festival. But for permanent structures? Just build a normal building.
Container homes can either be temporary and cheap and therefore literal Hoovervilles, or properly refitted and expensive, aka a waste of money. If you need a Pod then just buy the prefab Chinese ones.