Now that more and more countries are starting to go cashless (
http://www.bbc.com/capital/story/20180427-does-a-cashless-society-benefit-everyone), is it possible that we also start converting to cryptocurrency? If that happens, what do you think are the advantages and disadvantages? Paying virtually is very convenient for me as I do not have to bring cash and it prevents petty theft but what is the disadvantage?
No state can fully switch to using cryptocurrency only. If this happens, especially in many states, chaos will simply begin and the economies of the states will collapse. Therefore, no state will ever fully switch to the use of cryptocurrency. Cryptocurrency can go in the state only in parallel with the national money of this state.
The governments of all the countries sure understand it. That is why it will never happen. Even the countries where the crypto is legal will not convert to the digital money.