The Japanese Kamado referred to in the article is related to Korean Gamasot [1][2], with one crucial difference. The Korean version has a heavy, close-fitting, holeless iron lid that helps maintain a higher-than-atmospheric pressure inside the cooking vessel.
Higher pressure = higher boiling point = higher cooking temperature = different taste.
Korean rice cookers modeled after the Gamasot are basically autoclaves. The good ones maintain a pressure of about 2 atm and a cooking temperature of 120C. Unpressurized rice cookers are more common in Japan, and Japanese people are more used to the texture of rice cooked at 100C. Your sushi probably won't taste right if you cook the rice at 120C.