Banana plugs offer solid connection and convenience. When trying to wire speaker cables into the back of a reciever in a cabinet or other tight space, banana plugs offer the convenience of connecting the bare wire out in the open and simply plugging them in the appropriate post. This also prevents cross termination of stray strands that can overload the system. Additionally, the gold plating on the plugs offers corrosion resistance. Corrosion
(oxydation) can impede signal transfer and can potentially damage the terminals on your equipment. So banana plugs offer convenience, safety and equipment protection. Copper is a better conductor of electricity than gold but is much more susceptible to corrosion.