That's true but I think governments are more likely to go back to the gold standard (and claim they actually have the gold to back it up) than to adopt Bitcoin. Almost every government plan for their own crypto seems to insist on backing it with a physical asset, for example Venezuela's sham petrocrypto.
If the government makes gold-backed cryptocurrency but it's not tied to the actual gold value as collateral, then this is not a cryptocurrency expected by their people.
I'd agree with that. If that crypto would be tied to a resource, then it should be based on what the country currently does have, else it's really just speculating. Why peg it to a supposed amount of resource that is not even sure exist? The main reason people are thinking of backing currencies with metals like gold is that they are already tired of the current system where currencies are just traded around like stocks.