Honestly, I like her. She's fun, and her coming to the conclusion that Kyomi might be an absolute beast of a fuck machine is genuinely funny. She's also not trying to get in the way, just having emotions about the guy who got close to her in a very erotic situation. Which, honestly, makes sense. Of course she would. She's in high school.
Her being all flustered in the train while Kyomi was mostly just trying to avoid touching anyone was fun, too; as well as how we get confirmation that Nanjou might've been right to try and monopolize him when he's dressed like this.
So far, she's been fun. This would've been the chapter where we'd know if she'd be an annoying addition, but instead she's mostly just sort of a different lens to view our male lead. Which is nice, cause we don't have many of those.