Putin used to keep everything under control. Russian even an opinion can not Express freely. You think he might allow free circulation of cryptocurrency? Lol. I'm sure he will ban all cryptocurrencies except the one which is created by Russian. I will never use it. I would not be surprised if along with the code of the wallet to the computer is installed some kind of spyware. I don't believe the Russians and their currency.
Putin is not an idiot. I think you are right about national crypto and banning of other ones in Russia. But this idea is not new, Switzerland has two national currencies one of which only for business settlements. I suppose Russia is going to "stole" this idea, but they will use digital currency for their business settlements.