If crypto-money reaches critical mass in popularity and starts really threatening the power elite, then it will be used as reserves to issue redeemable notes and accounting entries on by the current banksters. We will then use these notes and accounting entries as money.
This is only viable if the people cannot create new money. So it will be solved by either creating another currency to avoid the control that bitcoin so easily affords, or dropping the idea that a limited supply commodity has any hope of being a legitimate replacement for fiat.
Inert notes offer anonymity, higher adoption rate in the local physical world, instantly verified transactions, and reversibility of transactions. The masses will have high demand for all these things in their money. It's going to be pretty much mandatory for true adoption.
Notes can be issued on anything, any cryptocoin, any metal, any stores of grain, any commodity, at any time. They're just receipts. But transacting commerce with these receipts offers all the benefits I just described. The non-physical, cryptographic, public nature of cryptocoins make it so the said benefits do not apply to commercing with the commodity itself.
Any entity that people trust not to evaporate and disappear with their commodity can successfully issue and redeem notes on anything at any time there is a demand, including right now. They just have to come up with a way to successfully identify counterfeits.
Sorry, but I don't follow how you think it is not viable.
I don't think it's possible to create anything that is impervious to: "You can give me that thing and I'll write you a receipt for it, and we can swap back anytime you want".
The fiat system is totally crapping itself. The only possible replacement is a limited commodity reserve currency. Any central bank that can is actively acquiring gold right now. It is far superior to the type of fiat system that exists as it does today. The only other option is government issued, debt-free fiat, but the banksters that run governments and the media won't let that happen.