The ruble was not convertible to foreign currencies prior to that though. If you lived there you could only exchange it for dollars/marks/etc. if you were travelling and only a very limited amount (and of course only well-connected people were allowed to do that anyway).
Besides international trade which was fully controlled by the state the USSR wasn't a part of the global financial system. The ruble was more like a token or a scrip (with very limited uses) rather than a real currency. Which is why the state managed to keep a lid on stuff there, there was almost no way for goods/money/people to get in or out at any significant scale.
Besides international trade which was fully controlled by the state the USSR wasn't a part of the global financial system. The ruble was more like a token or a scrip (with very limited uses) rather than a real currency. Which is why the state managed to keep a lid on stuff there, there was almost no way for goods/money/people to get in or out at any significant scale.