I personally think that both her debut episodes and the mothers day episode were enough to sell Kokoro for most people, of course she isn't gonna get focus episodes right after the extra cures join because that's normally how things work but she's bound to get a focus episode or 2 during the 30's. She's also a walking dictionary for idol terms for the kids at home and those who aren't really into idols as much. Hell the next episode is about idol signatures and that means Kokoro is bound to have a few good scenes there.