If Micchan knew what was going on, she'd give up on Natsuko. And that's what you need other friends beside your crush for, Micchan, to tell you things like that and make you accept them. And it's wrong to say Micchan needs Natsuko to affirm her greatness. She's desperate to win and keep Natsuko's absolutely worthless, cold, black heart, and the only thing she knows how to do is to keep trying to impress her. If someone told her another way, she'd desperately try THAT, too. That's made abundantly clear in both chapters - that she actually has very little pride or self esteem, and Natsuko flipped from overly worshipful to disdainful and sadistic once she realized being cruel to Micchan was enjoyable.