Super solid-silver AC cables are my favorite kind of HiFi silliness.
Silver is the best conductor. Check.
Big thick silver cables makes for the best cables. Check.
What about the miles of cheap copper in the walls, breaker box, from the house to the pole, etc? Got a voltage purifier of some sort? Awesome - what's inside that?
I learned a lot about power working on mainframes because bad power would make thinks wonky at best and disastrous at worst. We had a team we'd dispatch with Dranitz meters to log the power and man is there some terrible power out there. Good clean power is enough. The power supplies in the HiFi equipment is what they should be focusing on.
On the other hand, I totally get the "I want the best of everything" mentality and if some Bitcoin billionaire came to me asking for the best audio system ever and said that money was no object I'd definitely be charging him $18,000 for a power cable.