Bitcoin was launched in 2007. It's 10 years and still no country has approved Bitcoin ?? 
and in 2018, 2nd richest man "Warren Buffet" said "bitcoin will end up badly"
I am completely disagree with the statement that no country has still approved bitcoin because there are, I guess, 8 countries who has legalized cryptocurrency in their nation and people there are using cryptocurrency for their daily basis transactions. Though cryptocurrencies are being in rumors and now people are hesitating in investing into BTC but it doesn't mean that it will end up very badly because it has a very bright future ahead. and in 2018, 2nd richest man "Warren Buffet" said "bitcoin will end up badly"
Actually the countries which you talking about has not given the official legal tender declaration for the BTC but its just that they are not accepting the risk on their financial institutes/banks etc. The individual will be responsible for the whole scenario if something goes wrong! You can use it, you buy and sell in those countries but if you got scammed and ruined with your investment then they are nor responsible for that. However, a legalisation process would be something like Japan, the only country which is giving the legal recognition to the BTC and hence they can use it with merchandise as well as with personal purpose. Legalisation would be something that will include the proper amendments into the finance law etc.