Seems to me that the only important factors are the resistance of the cable/connector set, the impedance of the cable (capacitance/inductance) and the ruggedness of the connectors.
Refnoredcard is referring to the rugedness of the connector. I doubt that they are copper plated 'iron', most likely sheet steel. Most connectors have a plated steel base and that's a good thing. Copper is too soft and you would have a mashed up mess in no time.