Why do Japanese write Chinese characters when they write calligraphy? South Korea and North Korea also write Chinese characters. Are Chinese characters the most beautiful characters in the world?

In the Tang Dynasty, Japanese students were sent to China to study, but they didn't learn Chinese characters from China. After returning to China, they created a pen name based on the radicals of Chinese characters from China, which is now Japanese. South Korea and South Korea have been vassals of China since ancient times. Learning China culture, scripts are also based on Chinese characters, with different writing methods. Chinese characters are really the most beautiful characters in the world, and I like official script.