Why Are Condenser Microphone Diaphragms Gold-Sputtered?

It seems that “gold-sputtered” is a buzzword for condenser microphone diaphragms nowadays. Is this just good marketing, or is it a necessary part of condenser microphone design? Why are condenser microphone diaphragms gold-sputtered? Condenser mic diaphragms are often gold-sputtered since they need to be electrically conductive (to hold a charge across the capsule) but are typically …