AI avatars break in the second frame: different eyes, a different nose, suddenly a different age. That's why you get a reference catalogue, a set of photos of the character that lets a generator reproduce her faithfully every time, whatever the tool. On top of that, a character card with her personality: who she is, how she moves, how she speaks, what she'd never do. It gives her a character of her own, so she comes alive instead of being just a pretty face.