“Korean Age” is strange, different, and possibly not long for this world. The system uses a different counting method for ages, which can be confusing when interacting with the rest of the world, or even within Korea itself.
It is also a hassle for mothers who have a child born in December. In the new year, they likely find themselves having to answer the simple question of how old the baby is by elaborating that he or she is two years old by Korean age but is in truth only weeks old.
Unless I misunderstand, a baby born on December 31st would be “two years old” on January 1st, despite actually being just one day old. That’s very, very strange.