Currently cryptocurrency is being used by early adopters and techies. Also, in New Zealand, at least, Bitcoin is still seen as being used only by criminals, and 90% of people I talk to outside the blockchain space have never heard about "blockchain". (People have to be careful about living in an echo chamber.) If cryptocurrency is going to enter mainstream, ie the average person using it and most businesses accepting it, and more importantly the government accepting it, ie to pay taxes etc, things will need to change. Part of that change will include taxes. I agree that if they are set too high people will be encouraged to hide their cryptocurrencies - better to have a low tax which most people will pay rather than a higher tax which most people will attempt to evade.