Interesting idea, but one problem is that the current market cap of bitcoin is far too low for an economy the size of Greece. In principle for this to work you'd have to be able to completely "cash out" the national currency if everyone demanded their bitcoins at the same time. So if Greece had $100 Billion in drachmas issued, for example, you'd need $100 Billion worth of bitcoin backing it. But the current BTC market cap is less than $4 Billion.
Wouldn't the market cap drastically increase with it? That and $100 Billion in drachmas =/ 100 Billion USD their drachmas would be a lot weaker than the USD, Greece was just a hypothetical country and I see what you're saying but since Bitcoin is volatile just like gold the amount you would get per drachma would differ to, if everyone was to drop the drachmas at once for bitcoin the exchange power of drachma would be super declined making lets say their 1 drachma worth .000001 BTC
Let's say Greece declared the New Drachma, and announced they would issue 100,000,000 New Drachmas. And they promised to not print any more (except to replace those withdrawn from circulation/lost/destroyed), so the money supply would remain at 100,000,000 ND.
Let's say they promise and put it into law that 1 ND can be redeemed for 0.01 bitcoins. So in principle the entire ND supply could be converted into 1 million bitcoins. Since there are over 13 million bitcoins this could be done.
The problem lies in generating value for the ND. If Greece did nothing else, the ND would simply float with the price of BTC, and each ND would have a current value of about $2.50, with their entire money supply worth only $250 million. For a nation the size of Greece that simply wouldn't work.
They could force the issue by, for example, requiring all taxes, licences, fees, bills and so forth be paid with ND. This would force Greek citizens to use the ND currency. The free interconvertibility between the ND and BTC would then presumably force a strong rise in the price of BTC. The real question, though, is why the Greeks or anyone else would be interested in enriching those of us who happen to hold BTC?
It would make more sense for them to issue a new currency and promise, cross-my-heart, not to inflate it, with the same requirements forcing citizens to use it. And perhaps a way to do that would be to do as you suggest and tie the currency to a cryptocurrency - but a new one they design and release for the purpose, with no bagholders in position to be instantly enriched. It would be a challenge to coordinate and execute that without software bugs, exploits or mishaps in the mining community that would have to form. Not impossible, but risky without a well-conceived plan and widespread support from key constituencies and bodies of experts.
