Bitcoin is useful when importing goods from China to Russia. For the goods are paid with bitcoin, it is very convenient for the importer.
I think there are many reasons for the government to refuse to use Bitcoin rather than adopt it.
Different countries have different opinions on this, some countries have declared it illegal, and many countries have no policy or intent to regulate Bitcoin. Many governments may not like the idea of not being able to trace the identity associated with the transaction, there have been concerns about the use of Bitcoin by drug cartels or incidents such as wannacry rations.