She's judging the MC based on the fact he's a noble, while also hating nobility because everyone judged her based on her title instead of judging her as an individual...
What a moron.
Magnetism is another can of worms with 100 other sub powers like control weather, small gravity manipulation, light bending, and many overlaps like plasma creation and eletricity but way, way stronger.
Ngl, I would have prefered if the granny was a bit abusive and forced her to eat, at least the child would grow up being healthier. Picky children need to learn to eat what they don't like otherwise they may develop permanent eating disorders.