The interesting thing about rubles is that nobody knows what they are really worth because the current trading volume is so low.
Not too long ago there was the Big Mac Index for an approximation.
“I cannot forecast to you the action of Russia. It is a riddle wrapped in a mystery inside an enigma, but perhaps there is a key. That key is Russian national interest.”
Churchill
The only thing you need to know is that in China, Turkey and Gulf kingdoms they are accepted at the Moscow exchange rate. And so are in the money transfer systems.