The sword only has a duration of five posts, and a twenty post cooldown. Besites, it doesnt raise her POW, only the force of her blows specifically, and only when she hits with the sword. She can still be disarmed, or the sword could be unusable(like in a hallway or a cave). Remember that as powerful as the sword is, it's absolutely MASSIVE, which means she has to have a lot of free space to swing it.