Hanni already had a following prior to their debut due to her appearance on BTS' Permission to Dance MV and lots of fans assumed she was a Korean trainee named Cherry. I think this speaks to the fact that she could already be very trendy among Korean fans. Although there were some backhanded compliments from knetz towards Hanni at debut (that she was "pretty" because she was "Korean-looking"), many just found her visuals appealing because (1) she resembles many other Kpop visuals like Sulli, Jennie, Goo Hara, etc. and (2) she is able to pull off a lot of different styles including the kitsch style in Attention MV (I'm only quoting knetz). Then of course Hanni is crazy talented and stands out a lot as both a dancer and vocalist, which adds to her reputation as a sort of "ace" in NewJeans. Her charisma on stage gets her fancams to blow up and her international background (being Viet and fluent in English) probably makes her one of the more well-recognized members to international fans.
