Magickal Tools: Natural or man-made?

The older traditional Craft did not allow metal in the circle. That's slowly becoming obsolete. Practices evolve and change based on the practitioners, their culture and their personal views and needs. If someone uses an item with man-made materials that they feel got a satisfactory result for them, who am I to tell them that is the wrong way to do it? If I don't agree, I just won't use it for myself. It does no harm to me if others practice differently.