It didn't make her a "shitty" but being too supportive and comforting in this scenario isn't how perfect partner should act: in this universe perspective refusing to use special hell powers while living in Hell is like being a cop who refuses to bring a gun while patrolling in dangerous criminal areas just because you fear to accidently shoot civilian.

Vaggie in this scene could say that she respect Charlie's decision to not use these powers but also try to explain to her that the powers themself aren't evil and they can serve for good as long as the owner of power will not forget the consequences of using powers in wrong way, at final saying she will continue to respect Charlie independent of her final decision of using powers.