This series is an allegory, a story that can be interpreted to reveal a hidden meaning, typically a moral or political one.
This one is about Heteronormativity the belief that heterosexuality is the default, preferred, and normal expression of sexuality, and that it is the only natural or normal form of sexual orientation.
It's fitting that she is a ghost that refuses to let go, just like heteronormativity is like a ghost that refuses to let society free itself from it's control. The girl sees her boyfriend through a heteronormative lense. She doesn't see the clues that say she is not the one he is interested in, but as she takes the form of the boy, her heteronormative view is taken down piece by piece. She sees that she is not the person her boyfriend is interested in and that she doesn't actually want to force that connection with him, it isn't in anyone's best interest, denial of homosexuality makes all involved miserable, the straight people as well as the gay.
I think the rating for this series is too low, considering the message.
