Except you did not use google as a search engine providing a quotable source, but you used a google AI that you influenced with a suggestive question and weren’t even able to properly post the answer in a readable fashion to the forum.
Here, let me easily do the same for you in the opposite direction:
“why is ore not graded with i,ii, iii?”
Ore is not graded with simple I, II, or III designations because its quality is determined by the specific, precise concentration of valuable minerals (measured in percentages or grams per tonne) rather than broad, qualitative categories. Grades must be exact to calculate economic feasibility, as the “cut-off” grade depends on fluctuating metal prices and processing costs.
Instead of I, II, or III, mining operations use grade control (e.g., XRF analysis) to specifically identify, sample, and classify materials based on their exact economic and metallurgical value
Even if you would want to simplify and standardize it to I,II,III in the way that CCP does, which isn’t the way it is done in your real world, there is no common definition through all countries what highest and lowest should be. E.g. In my country the highest grade is always the first, but for CCP the highest grade is the last.

