Bitcoin is known as to be the biggest cryptocurrency. in some countries it can be used to purchase goods and services and some see cryptocurrency as a threat.
Not only in some countries but for every country where there are holders of it, we're all using it if it's needed for purchases that we want. It's for the application and contribution that we do because it's really made for that purpose.if Bitcoin comes to be number one currency in the world today, can it be hijack by the government?
They cannot, they can stop the exchanges but transactions will continue because it can be done through peer-to-peer transactions. It's useless if they will "hijack" bitcoin not unless there's an outlet that they will unplug the wire of internet connection to stop mining which will affect all of the transactions. 
