Bitcoin is legal by some countries but some countries still not accepting the bitcoin.
What you think is Bitcoin become legal in all countries?
everbody its happen to bitcoin become legal all over the world because this the goal of bitcoin community to become famous and use of all people as new currency.
It may not easily happen that btc will be legal all over the world to become the worlds global monetary system as it already opposed or discouraged by some countries like China, Bangladesh, Ecuador and other, Government of some countries may oppose this kind of system, why? transparency and the lack to rewrite the past transactions which is the governments hobby which so called corruption and control. They preferred central banking to impose heavy tax to the people. There will be a lot of conflict before that statement will happen.