If those old geezers in the central continent were to know of her existence, the human race would go extinct for sure. Killing Verra would be fine and dandy, but the possibility of another Verra coming along is as frightening as one appearing in the first place.
They banned Verra from using her innate ability. She became a part of the same protected class as Ari. A person so powerful that they could lead to the extinction of humans should their identity be revealed. Also, they are so powerful that once they mature will allow humans to stand at the continent's peak.
If not for Palmer touching her reverse scale if she had not lost herself. She would have never shown her power today. However, now that she showed her power, leave no witnesses behind.