I have wondered whether she tell this sooner or later, or not. It was perhaps a sort of accident for her leaking some KR ads. I thought she would embarassed and didn't know how to explain. but she proved that was my unnessersary worry. Thanks to her, VSPO vtuber group has been well-known in Korea. many KR fans fall into the rabbit hole through her. before she debut, it was ironically tokoyami towa of hololive who made a main entrance to know vspo girls(for KR bros), now Tsuna has taken that rule.
I'm glad at least she is finally upfront since most of her devoted viewers were already aware from the start. Personally, i think it's all about the timing to tell her fans about her knowing Korean since it would have been troublesome for her and VSPO if she had revealed it when she had debuted.
I've been wondering why she never talks about it. It's not like it's a heavily guarded secret. She's been friends with Cpt since her debut. I think many fans have been looking forward to her teaching her japanese friends like Towa, and Kuzuha the korean language.