Who wrote this article??? Lack of basic understanding of shorting a currency. If IMF really helped, Soros won't beat the bank of england by shorting Pounds, won't attack the southeast asia by shorting their currency either. Speculative attack typically happens when a country is overly loaned and there are plenty of fiat can be borrowed at a low interest

To short a currency, you just borrow it and then sell, in forex trading you can use leveraged trading to add to your power, and buy it back at a lower price. You can always short a currency on forex market, no matter there is bitcoin or not. And there is no such thing like you must support the currency exchange price by using bitcoin to buy your currency, you can always use USD reserve to support your currency exchange price

The only valid concern is that BTC might have devastating power over some small countries if its value gained too much, but that is another topic: What rich people will gain by destroy poor people's life???