I think all countries will not allow crypto as payment to their countries because every country has the authority and the law, but if 70% of countries in the world accept crypto, of course the price of bitcoin and altcoin will increase because of the many requests in the market
but that doesn't mean all will happen in 2020 because all still needs time
People are working on bringing awareness about the use of Bitcoin and Altcoins everywhere, as a result of it, it will be widely applicable throughout the world. The price of Both Bitcoin and Altcoins (Ethereum, Litcoins and Stellar Lumens) will increase as it is increasing with the period of it. We will not find a very high change in the prices, but I have high hopes with halving, that will surely bring considerable increase in the prices of crypto currencies.