Really? That thread seems to point to the opposite, although I haven't finished reading it. Also "The nickel plating is for corrosion protection. Copper corrodes fairly easily", so I guess that explains that.
edit: checked a few other sites and they all say copper is better than nickel but nickel is used to prevent oxidization.
edit: checked a few other sites and they all say copper is better than nickel but nickel is used to prevent oxidization.