Also "learn from mistakes" is taken for granted with quantity here, but it is very far from reality that learning comes inherently from practice. In the example, I would assume a student graded solely by weight couldnt care less about learning. I would create 10 pots reaching the minimum quality possible to be considered a pot and move on without looking back.

Also, it is very reasonable to assume that a student graded by quality would practice a lot and discard (and learn with) the worst pots.