Do you think Bitcoin will become the first world currency for buy and sell ?
I don't think so, because Bitcoin need expensive fee to do transactions, and I don't really like to use Bitcoin for transactions.
But I think Tokens will become the first world crypto currency for buy and sell goods and service, because I already find some project which have really great feature, that's like buy and sell goods and service using their tokens, and the fee isn't to expensive for every payment.
And I hope there will be more project like this and more developing to make us easier when we want to buy goods and service.