Gold plating electrical contacts does at least do something useful though, it helps to prevent oxidization/corrosion. A better analogy would be gold plated TOSLINK cables, which unfortunately do exist.
Exact same effect could be achieved by making conductor that very same single-digit % thicker. Which is an order of magnitude cheaper. And ohmic resistance is not that important for audio-cables anyway.
Assuming good contact in connector(s) is achieved, gold-plating does not further help with high-speed signals. What matters here - is wire/cable itself, specifically, tight control over where conductors are relative to each other and insulation, so that impedance is well matched throughout, cross-talk is minimized, etc, etc...