Did you misread the manga or something? She was literally stealing a girls childhood, and after she completed all the things she left unfinished before her death she has no desire to be in the realm of the living anymore. Shes not reincarnated either, shes possesing the body of the little girl...
I greatly enjoy reading the TL notes at the end, it provides an in-site into the meaning of characters names for those of us that don't speak Japanese.