REI and tsuki were the kpop idols who popularized the gyaru peace sign pose in kpop and so many kpop idols have done it now
Whenever something like this happens, people recognize the idol as a trendsetter. Chuu's Apple Hearts, Jihoons Save You in my Heart, etc.
I know twice j line did it long before rei and tsuki but they didnt popularize it. But since they're not the first to do it, is that why they're not acknowledged?