This means there’s no risk of default because the government can simply print money to pay off its debts. That’s how US is able to have national debt of $34.4 trillion right now. If The Economist thinks that Russia’s financial reserves will be exhausted in five years or so, then they have some explaining to do regarding the US.
The US is able to have a national debt of 34.4 trillion because people are still willing to lend them money. They aren’t just printing money, they are selling securities, which is similar to taking out a loan.
Printing more money in your own currency without backing it with some sort of security is just going to devalue your buying power and increase inflation. The Russian government is currently utilizing their reserves to sustain their spending, but if they run through those reserves they’re going to have to stop spending, or start selling securities. Either way, deficit spending cannot be solved via printing press.