Well, I read that the most friendly countries to the crypto currency are: Japan, Germany, Estonia and Singapore. Most of all I like Japan, this is the country where I can even move to live, since there are a lot of interesting things there, besides loyal crypto laws.
Japan is one of the most friendliest countries you could imagine. Knowing that NEM cryptocurrency has a lot of influence there, gives an indication of Japan's friendliness towards crypto. Japanese people seem to be very acquainted with the latest technologies. Which means that, they'll embrace new ones that are bound to change the world for the better (like Blockchain technology).
Usually any developed country is extremely friendly towards crypto. Only a small few countries like China and India have been against crypto, but that's bound to change soon. Russia was in the same stance as these countries, and now it has changed its mind. As long as crypto can be easily tracked and taxed by worldwide governments, then it'll be accepted as a legal form of payment.
The rest will depend on people's adoption within the mainstream world. Considering how viral Bitcoin and other cryptocurrencies became in 2017, the whole ecosystem will continue to grow into a solid workhorse for the world. Once crypto is strong enough, then it could easily compete against Fiat in many ways.
Nonetheless, with countries' acceptance towards crypto, new merchants and businesses could make use of this exciting new technology. As Blockchain becomes scalable enough to handle large TPS, it'll become the true replacement of our traditional financial system. Just my thoughts