> blockchain v gold
I don't disagree. Bullion has a proven history of utility and stability. For the time being, it should be the only form of money recognized by governments.
However, crypto is not the same as fiat. Fiat comes from the latin word meaning to order or command. A note of fiat is a command to do. While I am being a bit pedantic with my semantics, no one is forced to use a crypto and none of the existing ones can be owned or operated by a nation. A nation can hold cryptos (I don't think the systems are matire enough or have the proper feature set to work that way) - but they can't control the network… unless they create their own - which would then only have value as a fiat.
> blockchain and privacy
A valid concern. Monero (xmr) addresses this, as do a few others. Basically, because bitcoin has a record of transaction, it is not truly fungible. "New" or "clean" bitcoin sells for higher than "circulated" bitcoin. Basically, if a drug dealer buys from your business and pays you in bitcoin, some investigation could come to you and say you received crypto from illegal activities. Something that can be done with cash and serial numbers, but is much more difficult - and effectively impossible with bullion as it currently exists.
Monero addressed this by creating an encrypted ledger system as well as numerous other methods to obscure the origin and destination of transactions. Basically, if you get tracked using monero - it's because of failed opsec or classic gumshoe/humint methods. Well… i suppose a keylogger or something like that would work, as well, but that is outside the scope of monero vulnerabilities.