Having a country using colored coins in such small denominations as their cash requires a lot of tiny transactions. This cannot be done on the blockchain as the minimum transaction needs to be around 1k satoshis. It would need to be lightning network based. You would likely need some centralized lightning nodes to handle the transactions because on the Lightning Network you cannot see the source address. So you could send some non-colored coins (bought cheap) to the colored coin network.
I have not figured out this technical challenge.
It appears that this technical challenge is being overcome by the development of RGB.
I have also learned that many countries are trying to figure out how to have their own crypto currencies based on Bitcoin becoming a bit more mainstream. I do not doubt that within the next 4-5 years there will be some nation in the world that adopts a cryptocurrency or allows it for payments of government services.
This strategy would give the nation a transitional period while also providing them the huge benefits of a currency with DEX, smart contracts and fast low fee transactions.
I have spoken to some people here in Panama that are open to the idea (Panama uses a national currency pegged to the US dollar). The government started working on a cryptocurrency during the pandemic when they were giving out food vouchers to people, they wanted to have the cryptocurrency used for the vouchers accepted at all of the grocery stores.
We already have stablecoins in Tether, DAI, USDC and others so the idea is not too foreign. Having a stablecoin using the Bitcoin Lightning Network that eventually transitions into the nation using bitcoin as their currency would be even better.
It looks like they plan on inflating the dollar to trash status, in so doing they would eventually lose Panama as a nation using their currency. And Panama would then prosper with a currency that doesn't purposefully lose value over time (they really get screwed by using the dollar, the US prints the money and spends it while Panama's currency loses value).