We obviously know he's not gonna do anything and any awkward situation she puts him in won't be misread by Hoshino so that's not the interesting part.
Moreso it'll be how he deals with this girl and how it's portrayed, if being promiscuous is seen as bad and something that needs to be "cured" or dealt with or whatever. Would be a nice change of pace if he gets into this with the why and shit and she just ends up choosing to sleep around anyway. Other than that it really is a little unclear what she adds to the manga at this point other than some more annoying outside pressure on a relationship that has a really weird "keep it a secret" clause anyways
Was this manga not finished? I remember reading the ending...Was it spoiled? Am I going crazy? (I know the freaking ending, I just don't understand if it was ereased, if I saw it on another site...or wtf is happening)