TLDW: They were popular in the 1940s and when they fell into disrepair and became environmental hazards the ordinances banned them.

The video author tries to make the case that they're actually superior to conventional homes and that the bans lack proper engineering analysis and other comparisons, but I think it's actually a lot simpler than that: you have a much easier time tearing down, bulldozing, etc a building made of wood, brick, stone, or mud than one made of steel beams and panels.

I think the innovation we're all waiting for is curved ceramic beams, similar to the rebar alternatives on the market.

Too bad we'll never know

Regulations

It's not "banned in the USA" - most likely whatever this video is pushing simply doesn't meet code in some way.

I see WWII-era quonset huts everywhere, and they've likely been in place since WWII or just after.

A friend built this as a garage on a horse farm recently. So clearly the buildings aren't "banned".

Just more BS