If all countries can accepted crypto currencies in there various countries, as a means of payment and as a means of online exchanges, such as money is, money is anything use as a means of exchange and general acceptable. With the means I think all cryptocurrencies (bitcoin) will definitely go round the world, and will be use as a means of exchange. I will be so grateful to the creation of crypto currencies. This will also help our future generation, Remember something when we do international transfer across the countries, it may take a while to get the money to your local bank account, but with cryptocurrency you can get instant reflection if bitcoin etc is transfer to wallet,And you can make use of your coin (bitcoin ETC).
Yeah, it is not going to happen. Not any time soon. Look at how the prices of the coins fluctuate. Looking at how volatile the currency is, it is not feasible to accept the bitcoin or other decentralized crypto currencies unless you accept and directly convert it to fiat currency instantly. There are services that do that for you, but this doesn't mean that "you" are accepting crypto currencies. Lets not forget about how insane the fees become where there are sudden changes in the market price.
You can indirectly purchase with bitcoins though. Buy giftcards with your coins and use those bitcoins to purchase online.