No doubt tax is one major avenue for any government to raise funds for her projects and activities. The West don't joke with tax matters and frown at evaders. Many individuals and companies always seek for avenue to hide their wealth and evade tax technically.
Many had long devised means of taking capital flight to safe haven countries to hide and protect their accumulated wealth.
Now comes the crypto industry where you can hold billions of dollars in a decentralized wallet and walk around like you don't own nothing. No Forbes to track your worth or expose your hidden wealth. This is one of the major reason countries are showing restraint in crypto currency approval.
Terrorism could easily be financed with or without a trace and drug cartel would easily flourish in this system or industry. In the same vein, it is also an opportunity or avenue for some country to curb devaluation of their currency through crypto adoption. All countries are trying to workout modalities for its adoption and implementation but one thing is such, government of nations cannot be in control again like they do for banks.
Germany, El Salvador, Switzerland and Portugal are amongst the countries that are now offering tax free financial system for crypto holders. Other countries are coming up with their own policy too but as time goes by, there would be more and more fine tuning. For Nigeria, we wait for October 1, 2021 for another policy statement from the nation's central bank.