I'm kind of amazed at how well this works. Chieri is an idol fan, so even when she goes back to being herself all of the stuff Ichika said would still make sense.
Oooh and Chieri-as-Ichika has yet to meet Ichika's other idol members! And since they're living together, the school girls might meet the idol girls for maximum chaos! The potential is limitless.
You are right and I find it amazing... but also lowkey hate it...?
I can perfectly see Chieri growing more confident, able to raise for heself and others, and Ichika learning to grow stronger deeper conections (as I feel thats probably her deal/personal dilemma).
So once, they go back to their own bodies, maybe nobody will notice the change. And thats kind of scary and terrible.
Chieri will return to her body, losing her career as an idol that maybe she grew to love, and find that suddenly she has a lot of friends (some of them crushing after her), but in truth those friends grew to like/love Ichika-in-her-body, not her.
And Ichika will return to her body, missing the peacefulness of being a regular student, and find a lot of changes on the personal dynamics with her idol group (which based on her fear/dislike of loneliness, I suspect she didnt get along with them), with the other girls being now a lot more closer to her (maybe also having crushes on her), but in truth they grew to like/love Chieri-in-her-body, not her.
Its kind of a mess. And it would only solve if they end up telling all of them the truth (which may or may not happen) or if they remain in each other bodies forever.