There is no such thing as a filler member. A lot of times I see people saying that "oh xxx is useless" or "xxx is a filler member" and I'm like who are you to call them a filler member? Unless you tell me that member has got like zero charm and absolutely zero talent then yes fine whatever I guess.
Of course not everyone in the group is going to be equal in terms of singing or dancing. I mean we can judge these traits objectively. However, even if that member is not the most skilled in terms of vocal technique or dancing, if they make up for it by the very simple act of attracting fans to the group, then that member has done their job. Like they can do so through their personality, or through visuals whatever, if that member is a stan attractor, he or she has fulfilled his or her role in helping the group get more fans and helping the group gain popularity.
As far as I know, there isn't really a member in a group that is a "filler member". I mean, if the member is someone like Hwayoung who makes the group worse by causing a huge ass scandal, even that she isn't a filler member, she's just a screwed up snake 
, I call her a sabotage member, a member than literally joins the group to make everything worse.
Stop calling members who are stan attractors filler members when they are there contributing to making the group popular, where you are just there sitting behind your computer or phone that your parents probably bought for you, and thinking which is the next victim you wanna bash.
kthxbye
, you spilled out some facts 
