>>45125919Because they're the ones who made it and there's no reason not to celebrate their franchise that is probably the most popular multimedia series worldwide.
Additionally, it would just appeal to them the same way it appeals to all of us here and other pokemon playing communities.
There's also the fact that Pokemon are a hell of a lot like Yokai, so it's more culturally resonant for them than it is for us.
And it just fits a lot more Japanese sensibilities than it does Western. They love cute stuff over there, and they love monsters too, and the idea of guardian monsters/spirits is another big thing in Japanese mythology, and turn-based combat with level-up systems is another thing that is very popular in Japanese games.
Pokemon just hits a ton of the Japanese-appeal points in addition to being just fun and enjoyable for everyone.