According to the news release for developers, Apple has shifted the Korean App Store to the Korean won price away from the US dollar. This movement will affect both downloading the app and in-app purchase.
To be fair, the only surprising thing for me is that Apple only priced the Korean App Store with dollars, but it is important for developers and consumers in that country. It may also help Apple to increase sales in that market.
Apple's Korean App Store announcement
From Apple's Developer News [emphasis added]:
From today, Korean apps and in-app purchase prices will be changed from US dollars to Korean won. Sales revenue in Korea will change to won, You will continue to be paid on the currency you chose for your bank in the App Store Connect.
This news will only affect the App Store in Korea.