There's nothing that ties Knox to the Korean market. There are some valid security advantages for using it and it was some years ago when the US Department of Defense added various Knox-enabled Samsung models to their list of approved devices, which is most likely quite a short list.
In addition, I'm not Korean and not using Samsung everything and still I'm running Knox for reasons stated in a post above.
If it were designed for the US market, it would be a flop. Unless it's just a flop.