THe NK developer will think, wait, I'm making a fraction of what I'm actually earning, I will smuggle in a Starlink receiver and set up a bank account in China and work for myself. This is how Communist regimes end.
The one who did the interview and the ones who do the coding may not overlap, and as OP mentioned, they don't need to be particularly good. Even if they get fired after a few months, it's still a net win.
> They are often required to leave family members behind as collateral to prevent them from defecting while outside their home country.