I mean Watanabe being as she is either for comedic value or her being that way as the core premise of this series is fine and all, but everything else is built in a way, that reflects poorly on the girl. Unless I am to dislike her for now. But even then, if I do, I'm not too eager to root for her and Yoshiokay, which seems to be the end goal here.
There was one moment where it seemed like she would start looking at our Gyaru girl from a better light, with the sister stuff, but it just... It happened and was forgotten. Frustrating, especially since I really want to like this.