I guess that in the coming decades, more and more African or Latin American countries will tend to use Bitcoin as their legal currency, which can help them resist the erosion of the US dollar. However, the Super Congress insisted on issuing its own legal currency and controlling its exchange rate with Bitcoin. I guess that for China, the final result may be to ask the public to hand over its bitcoin to the country and give it the equivalent value of CNY.
It's way too early to make such predictions, we need to see how El Salvador's experiment will play out. If it will flop, few countries will want to repeat this, especially with programs like giving away pre-loaded wallets, or just updating their infrastructure to accept Bitcoin transactions, which can be too costly for poor countries. It will take 2-4 years to see the results of El Salvador's decision.