Who on the earth want "national crypocurrency"? It's the opposite of what Bitcoin trying to achieve.
The answer to that question can be seen clearly. It is a well known fact that government doesn't like anything that cannot be controlled, so they made a national cryptocurrency in order to harness blockchain technology without using decentralized cryptocurrencies. In short, they want to use a cryptocurrency that is not decentralized in order for them to have control over it.
But the whole point of the blockchain is that it is decentralised. As soon as you centralise it, you can attack it.
Even the decentralized blockchain still can get attack just like 51% attack.
But as far as I can see the fact after maduro was issuing its cryptocurrency and there are some countries are of same interest to doing the same thing just like maduro too.
But about the point why those countries are interested in issuing their own crypto due to the global trend.