Bitcoin is legal by some countries but some countries still not accepting the bitcoin.
What you think is Bitcoin become legal in all countries?
I think bitcoin will not be legal in all countries .. for example in my country .. the government prohibits sale and purchase transactions using bitcoin .. the reason is because bitcoin is not a valid currency and we also know in India in this time prohibits the existence of bitcoin.
but my hope is that all countries in the world will later legalize bitcoin and leave the local currency.