External payments are a different kind of bubble with various companies entering the market, but they'll eventually be weeded out. Furthermore, external payments are only effective for games with long-standing services that have a lot of so-called 'whales,' like FGO, Monster Strike, and Genshin. I don't see app-external payments as a silver bullet for Japan's declining gacha games. After all, a higher profit margin is meaningless if the user base is shrinking.