Very random but what is the obsession from so many JPop-artists, that they write Korean hashtags onto their Instagram?

I saw like 500 JPop-artist's Instagram-accounts and almost half of them uses Korean hashtags on their posts. Anyone has an idea why that could be so?

Quote from BAPbabyyyyyy

They are trying to get the algorithm to expose kpop fans to them and their music or content. You know to get advantage of the attention on kpop right now.

if that would be it than they would write kpop-idol names or groups in Hangul, but they don't do that