Who chose that name???? Sorry but why is it so bad(っ˘╭╮˘)っ

The group name actually based on the real youtube idol group. I think the webtoon was made based on them as the characters. So, it seems the webtoon come to existence because the group already existed.
And the character personality was keep as it is based on the idol's characters in youtube.
Watch them on youtube! Their voices totally suit their characters!!
Just search: Millionaire Official