First of all, the cryptocurrency must be known to more people. Secondly, the national government needs to be recognized, which will speed up the promotion and growth of cryptocurrency. I hope to arrive sooner.
It needs to be regulated by the government first before it becomes a legal tender of payment. As a medium of payment, some people are already using it including me when I wanted to pay my bills because we have a platform wherein we can pay our bills using cryptocurrencies so it makes it easier for the crypto users in our country to do such thing. The scope of being a successful medium of payment may be small for now but later on, it would become larger.
most governments agree with this technology and some disagree because the reasons are so vulnerable to misuse by irresponsible people. therefore cryptocurrency requires legalization around the world as an alternative to how to transact valid payments, so that its function can be used by all people around the world.
Some governments are concerned about ICOs because these are securities offerings and therefore should be regulated by Securities Law. Many ICOs evade Securities Law and this is why some governments have prohibited ICOs. This isn't the same as prohibiting the use of cryptocurrency as a medium of exchange.
I'm not aware of any government that has prohibited the use of cryptocurrency as a medium of payment. So, that means that no cryptocurrency is illegal to use as a medium of payment.
I agree that governments enthusiastically supporting a cryptocurrency as a medium of payment will help in people trusting using this cryptocurrency.