What Russia needs dollars for? The US is not her serious trading partner, but China and India are.
Dollars convert easily. The Yuan and Rupee do not convert well. Yes, you can trade with India and China, but then you give a lot of leverage to those two countries. The US will have Russia in a box. Russia needs the flexibility to trade as many places as possible. And dollars are the universal currency. Euros are almost as good. And Yen is a close third. All are nice strong currencies that will just go up in value as the NATO countries attack the Ruble. Russia has oil and gold. Both can be sold for western currencies. And both are strong.
Where were numerous threats that Russia won’t be allowed to convert, and tons of her dollar reserves were seized, so dollar is losing its shine.