I don't see a return to precious metals for one reason: convenience. Yes, in this day and age, especially in China, there is less cash. So it's not going back to precious metals.
You might be right and another reason for Bitcoin is that online factor and easy integration. But this alone is not really why gold will be a declining in usage, its easily possible to use gold in a proxy form and if your standard is centralised anyway and trusting higher authority in a conventional way then gold is just fine as a tradable service.
You can hold the gold centrally and trade notes of worth that have a claim on that gold deposit. That system works fine under most circumstances and has been normal for hundreds of years, the gold is settled when a larger amount is accrued like settling a credit card
As I've said before, there's no way in hell gold or any precious metal is going to be used the way it was before 1900. Not even if there's a zombie apocalypse. The world has moved (and continues to move) so far away from physical cash that we're past the point of no return right now.
I'm always reminded of the Tide going out on a big beach when I was a kid. It always seemed like the sea had gone and would never return, the plug was pulled in the seabed and this situation was irreversible. It was barely in sight or at least at knee height only that was my view of the world.
Thats how people view gold, since 1971 gold has gone and it will never come back. How could it come back when its been gone my entire life. I understand why people would say that with respect to technology but gold has been outdated thousands of years by other ideas and ability to transfer value without a heavy rock. Yet gold remains, its useful and unique and part of the money system I think forever.
The tide will turn, we will once again be using gold every day. High tide will be surprise to everyone as we again are upto our chins in water in once what was only sand. Change is not just possible but inevitable imo
[I live near the worlds largest tidal range btw, hence my memory of these epic beach ranges]
Bitcoin is what many people believe is that change, but its only one part of the story we will see happen