that would be a difficult prospect because the crypto currencies are still very volatile and that would spell further economic problems for a weak economy because noting in that country could be stable , the cost of an item would also have to be volatile for example if your using bitcoins and you bought an item for re-sale and the price for a bitcoin went up that would there fore mean that you would also have to amend the price of that item to reflect that increase. That would make absolutely no sense as you would have no idea exactly what your money is worth or what portion of goods it would pay for.
Why should the state use cryptocurrency? Fiat's money, too. Initially, Fiat has real value and any government has the opportunity to support this value. But the problem is that the government doesn't know how to run the economy. They are always spending more than they earn and compensate it at the expense of inflation. They cannot exist in a fair economy.