We are in an era where in mostly everything is run and use the power of technology, so as the cryptocurrencies. Becoming the national money is not far from happening. Yes it may be volatile, but it shows progression each year. And it this continues, the possibility of it is a big chance.
It is completely possible that governments create their own official cryptocurrencies but the issue is who is going to use those coins, the general public is not using cryptocurrencies yet so they wont use a crypto created by their government and for those like us that do use cryptocurrencies I would guess that most are opposed to use any crypto created by a government.