Penny went on to add everything she would need. With the possibility of the land falling into a land where they would end up with spilled magic, there was no telling that the magic she had learned would work. The black witches were tricky when placing traps in a way where the white witches who were under the transformation of turning to black witches were able to use spells but the same could not be used by the pure white witches.
She would need a lot of weapons, weapons that could eradicate a number of witches in one shot or immobilize them and she knew the white witches in here were working on it. After losing a bunch of white witches in the second council exam, the people who were still alive and were part of the church had started to create weapons that were concentrated on black witches.