Connectors with silver contacts can be designed to be self-cleaning (i.e. clean themselves on connect/disconnect). Silver can handle higher currents than gold, which is important if you want the connector to survive hot-swapping. Gold also tends to wear off with repeated connect/disconnect cycles.
Do you have any resources re: gold and current capability? I see lots of gold-plated connectors rated for 20 A or more.
From my link above:
There is an absorption layer built on top of the hard gold surface, which can be broken very easily with very low normal forces. Similarly, the coefficients of friction and, thus, the insertion and withdrawal forces of gold surfaces are rather low. This leads into very low wear and, therefore, to a high number of mating cycles. Thus, gold is also suitable for low voltages, corrosive environments and ideal for coatings of connectors in the data and signal range. The main disadvantage of hard gold is its high cost and its price-dependence on the stock market.