

South Korea is infamous for very high cost of living, especially considering the very low salaries.
You can check numbeo for more specific comparisons, but Seoul and Busan are only 20% and 30% cheaper in terms of cost of living compared to Atlanta GA, respectively. Not nearly enough to make up the salary difference.
The fact there there are migrant workers already tells you the situation. People’s behaviour generally follow economic incentives. There’s a reason why South Korea is struggling with emigration.
As suspected, this paper is based upon Paul Ekman’s Facial Action Coding System, better known as micro-expressions.
This controversial literature borderlines on pseudo-science, with Ekman’s work having significant conflicts of interest in the form of undisclosed funding from US defence, police, and border control, who wanted Ekman to create systems that can detect lies based on supposed micro expressions. Subsequent independent meta analyses have found that micro expressions cannot be consistently read, even by Ekman’s own researchers.
Unfortunately, despite this, world governments have poured millions of dollars into private contractors to develop AI systems based on this flawed research for border control.
Munecat’s video essay on debunking body language experts goes into much greater detail:
https://youtu.be/Y0VQyEY-B2I