If you live in even a remotely wet climate, shipping containers will inevitably get rust/mold, the amount of nooks and crannies that you don't have access to, but water does is insane
The acoustics are also shit, you will lose your mind with the constant clanking and echoes
They also have no insulation whatsoever, you will boil alive or freeze unless you bury the fucking things but then you have rust and mold issues
I suppose as temporary forms of shelter they're fine but for making long-term viable housing it's a non-starter