No bitcoin can not become a global currency the governments around the world would never agree to it.
if all of the governments never agree with it then why do you think bitcoin is still acceptable on most countries these days ? thats only a reason that most of them will agree to use bitcoin but some that bans bitcoin dont agree that bitcoin can become a global currency .
why bitcoin can not become a global currency ? because bitcoin is still not yet accepted globally . soon if other countries accept btc , i think its possible fo btc to become a global currency