it's something very integral to her character i think. because in theory, there's not much in kira that should even drive her to be an idol. she's Very far away from that ideal! because an idol is always kind and uplifting and perfect, and she's... well. kira is a bit of an Ass, and i say that with all the love in my heart. she's jealous, and proud, and holds grudges, and. well. can't sing. but in practice, she's exactly what an idol Should be!!!!!! because kira is completely aware of all that. no matter if she, at any given moment, acts according to her heart or her mind, she's aware of what she lacks- and she Works on it. through training to sing, yes, but also through going against her instinct and being just a bit... nicer. this really shines in the later stages of her dynamic with misteln, i think? as in, kira is still petty and gets annoyed easily but she tries. she apologizes even if it's pretty awkward and she Tolerates misteln, inwardly more than she does externally. and even despite her general demeanor, it's obvious that the "idol spirit" that she thinks herself to be incapable of truly achieving Does exist in her, even with all her flaws... she Does lift up whoever she can, whenever she can.