Ever dreamt of converting a shipping container?
It’s not all it’s cracked up to be. Here is a great explanation of why. Quick takeaway: the costs and effort to make even the steel walls suitable as a residential wall are not worth it. The only advantage is the corrugated steel look, but you can get that buy buying cheap roofing and using it as cladding.
A good framing crew could build a structure of similar size and complexity (it’s just a box) in a day.