In addition to their usual national money and non-cash forms of payment, as well as cryptocurrency, the state can and probably will use it in the near future.
However, it is never possible for the state to fully switch to the use of cryptocurrency, it is simply impossible. Cryptocurrency is not intended for this. It can exist only in parallel with the national money of the states and cannot replace them.
It is impossible for all countries to switch to the use of cryptocurrency, because not all countries have internet access as in developed countries. While the internet is a means to conduct transactions with cryptocurrency. The most likely is cryptocurrency as a companion currency for fiat currencies, so users have a choice.