Despite the massive growth, advancement and advantages of Bitcoin and most crypto currency, why is it hard for most countries to fully accept it is or permit it's exchange?
Bitcoin is decentralized, which is why governments had a negative attitude towards Bitcoin from the beginning. But when they realized that they could not restrict it in any way, they started adopting it.
For some reasons, governments cannot be willing to accept Bitcoin. Normally, central banks can printing money according to their needs. But in the case of Bitcoin, that is not possible because they cannot control Bitcoin.
Bitcoin uses blockchain technology to make transactions. Users can make transactions without banks, which is why governments lose financial control over those users. After all the positive side is that governments have now created a positive attitude towards Bitcoin.