I think the ruble is in for a wild ride and that these interest rates are a clear red flag. What I would do is go ahead and put some rubles in one of those high-interest accounts and use them in the local economy for my everyday purchases. But there's no way in h€ll I'd go rushing in with my dollars to buy rubles. I've lived as an expat too long and been burned enough by even moderate exchange rate fluctuations that it's not the kind of speculation I'd enjoy. (And my time has all been spent in countries with much better rule of law than Russia.)
For comparison, I'm an American expat living in a eurozone country. I have savings in USD and EUR but a carry trade housing loan in CHF, which is currently low interest (yay!) but killing us on the exchange rate (boo!). In retrospect, it was the lure of the lower interest rate that "sold" me on that loan, but during only one month of the six-year loan period (so far) have we been able to purchase CHF at a better rate than we borrowed. All the rest of the time it's been worse (and usually much worse, as you'll know if you've followed the CHF issue at all).
If we keep the loan for 30 years we may or may not come out even (lower interest costs and higher exchange rate may cancel each other out), but the tricky part is that it's really impossible to know or predict.
