So, you are here to prove Yuki point, that she was interesting only because she was Catulus, and not for who she actually is.
While I do understand your point of view, I have to disagree. Since Yuki is a congenital catulus, being a catulus is who she really is. All of her friends have only known her as an catulus - and are mostly catulus themselves. So in my opinion by taking the medicine, Yuki no only changes into a person she never was in the first place, she also assumes that all (other) catulus in general are only interesting because they are catulus. Thus implying somewhat, that "normal" humans are better.
Denying a part of your own personality just to fit in with the others is bullshit. And to be fair: the story sets off because Yuki is a catulus. She is insecure, turns into a cat and Ayano has to deliver her clothes back to her thus hitting it off with each other. And I believe that's what Ayano was saying: If she wasn't a catulus - which Ayano has known before - they would be normal classmates and maybe have had a slower start.
While my kneejerk response to your original post was rather negative, I do agree that I'm not a fan of this development should the medicine have a permanent effect on Yuki.
What Yuki did is essentially throwing away what makes her special in hopes of seeing whether her relationship with Ayano is genuine, or was it merely one of the effects of her being a catulus. Kind of goes to show how much Yuki is willing to give up there, but yes, being a Catulus is an inextricable part of who she is. Yuki turning back into a Catulus would actually be the perfect scenario: she gets to see whether their relationship is genuine, Ayano gets to see how far Yuki is willing to go for her, and Yuki does not need to become someone she is not. Could also help her get over her insecurity, which ch.98 is kind of hinting at, I feel.