In my experience it's down to how good the contact is and whether it gets disturbed. If it's clamped tightly and rarely moved then copper or sliver are fine, if it's a press fit (like RCA, XLR or banana) then gold on gold eliminates worries about corrosion and the softness of the material ensures a good contact surface area. There is no benefit from using rhodium outside of a caustic environment.
What's the best plating material for interconnects plugs ?
Does anyone has opinion on whats the best plating material for connector plugs, is it silver, gold or rhodium ?