But, it is a better idea for a country to invest in it, like they invest in gold etc. because it has got huge potential. Once they do, Bitcoin will be more valuable and more people will start using it.
But accepting it as an official currency will get the country broke.
If a nation would just buy Bitcoin it would be speculation and not something that nations should do.
If instead the nation bought Bitcoin and announced that it's their new national currency that taxes must be paid in, it would create huge demand for Bitcoin compared to now and it would increase it's investment's worth by a big factor. Just like going from paper that costs four cents to print to being worth a hundred.
This is how Romans did it. They announced that taxes must be paid with this coin that has a picture of the ruler and gave the coins to soldiers to resupply themselves on their way to new battles, which citizens accepted because it was the only way to pay tax to the government.
This is how every nation gives value to it's currency. They create the demand by law. Law is backed up by violence and thus Bitcoin's value would go up violently.
The great thing about this is that it will happen for sure, because of greed. Bitcoin is faster, cheaper, more secure and private than the current system. The exciting thing about that is that Bitcoin's wide adoption will eventually end nation states and thus free humanity from the violent concept that a nation is. War is a side effect of nations and only a psychopath is against more peaceful future.
What's absolutely exhilarating is that this is a self-fulfilling prophecy. Just because the idea is out, it will happen. No force on earth is big enough to prevent this happening.
The question remains, which nation first?
