Yes, I actually have been in contact with the Korean bitcoin scene since 2017 and understand the Korean ecosystem better than many.

Korea and Japan have a lot of similarities such as active traders, conservative culture, love for altcoins etc...

With that said, there are interesting differences between the two in my opinion.

Korea is a bit more international/Americanized than Japan in general. Leaders in the crypto community are often bi-lingual or Koreans who grew up overseas. This gives more advantages for Koreans to keep up with the latest trends in the English speaking world and compete internationally.

On the other hand, Japan is a bit more detached from the English speaking world and English proficiency is weaker, which makes difficult for international projects to enter the Japanese market.

The key advantage for Japan is that it has developer culture and a group of people who purely enjoy playing with new technologies beyond profit making. Hence, we manage to bootstrap a very active routing community with Diamond Hands, and now the same group of people are very excited about BitAxe, a DIY solo miner.

BitAxe, for example, won't make you any money but a number of people in the Bitcoin community in Japan are excited about playing with this new toy, understanding mining better and contributing to the network. This type of culture gives an edge to Japan in terms of creativity and innovations in my opinion.

On the other hand, I see less movement like this in Korea and people seem to be more pragmatic or less interested in things that don't make economic sense. It's reasonable but it's probably more difficult to build and maintain a Bitcoin community with strong culture in Korea.