Now we can see some countries are regulating bitcoin and some government don't like it.Otherwise Bitcoin hasn't a stable price.
So my question is can bitcoin be a main currency of world economy?
In my own opinion, bitcoins can be the main currency of a country only if those government are going to legalize cryptocurrency in their country since most of the people today wants faster transactions.
Since bitcoin is yet to be regulated in some countries and even banned in other areas, becoming a main international currency does seem like a fantasy to bitcoin. I think the answer for this lies in the nature of bitcoin and what it could do to the governments and their monetary system. Take my country as an example, although there is no laws imposed on bitcoin and cryptocurrencies, the government has started to pay more attention to bitcoin in a negative way and they think that bitcoin is just another tool for criminal actions. Therefore, they try to limit the use of bitcoin and I heard on the grapevine that they will ban bitcoin some day. I surely don't hope that this is the future for bitcoin here.