So my question is can bitcoin be a main currency of world economy?
Bitcoin's a currency that has great potential, to become the world's major currency if the government approves and legalizes bitcoin for use. But along with that, bitcoin still has many obstacles which one of them is the amount of supply which is very limited so that this's unlikely to be able to supply the entire human population in the world.
Bitcoin is a good coin to invest as a kind of asset but I think in order to become common currency around the world Bitcoin is hard to make because it still has some limitations such as quantity, The transaction speed is slow. Coins are likely to become the common currency of the world I think is XRP.