Seems pointless to me. No one can explain why uber copper should sound better.
Let me try.
I come from the semiconductor industry and we have a very different take on conductivity. Copper is a conductor. Carbon is a semi conductor as is copper oxide. Cupric oxide and cuprous oxide are crappy conductors.
https://www.researchgate.net/post/Why_are_the_resistivity_of_Cu2O_and_CuO_so_differentThe major contaminates of copper (ETP copper) are oxides of copper. Some of each typically along with some carbon.
What happens is carbon and copper oxides form around the crystalline structure of copper (or any other good conductor) and when this occurs there is a semi-conducting barrier that is formed around the crystal. Any time this occurs what we have is a very crude diode layer between copper crystals. This is why UPOCC is so popular. Instead of having copper crystals that are any where from tenths of inches long to several inches they are over 1000' long. No diode effects to speak of. Diodes ring. They have time delays and reverse currents, no matter how trivial. Multiply this by films that are 10-12nm thick and you can see why metals and other conductor purity in the semi industry is so crucial. That is also why most modern FABs run class 10 cleanroom atmospheres... or better.
This is a huge over simplification, but it is a frame of reference.