There is a country whose fiat systems failed and they switch to crypto: Venezuela. The bad news is, they don't use sound money (Bitcoin), but they create their own cryptocurrency which doesn't essentially remove the manipulation from the government. I tend to believe that if they choose to use Bitcoin as their market money, their disaster could be avoided. Just like when country use gold as the money, where money is a market good not something created out of debt.
I really feel bad for Venezuela for not relying to bitcoin but they just can't, a government can't be dependent to a decentralized money. They have to obtain power from it so they can control it.
There are citizens there that are relying to bitcoin to flee from the hyper inflation that they have been experiencing today. And for their very petro coin, I don't think it will be able to survive for few more years.