Venezuela already has its own state-backed cryptocurrency called as Petro but I am not so sure if it is really a very successful one. Any update on Petro can be appreciated. Anyway, cryptocurrency is an open technology, so anybody can make his own crypto, much more a country no matter how small or even big. Now, one of the most important features of cryptocurrency is decentralization and this is one big lacking in state-backed cryptocurrency because the government at hand is always in control. How these state-sponsored digital currencies will be faring in the future depends on many factors, and it is hard to predict based on things existing presently. Hope they will also be successful because those currencies can actually be linked to real cryptos.