I think country are scared of crypto because they can't follow what you do with crypto, they will not be able to follow your transaction and benefits and thus they will not be able to tax you.With crypto which keep you anonymous people are able to purchase illegal things and not being spotted.They are also probably scared of the volatility of the market which can cause loss of money for people. I think the high instance of countries should be more informed about cryptos in order to make them more populare.