It think it's still too early to say that Bitcoin is a global currency. The reason is not the fact that some countries restrict the use of it, since there are actually a few countries taking such measures.
The main reason, in my opinion, is that there is still a small percentage of people using the currency compared to the number of people around the globe. So, it's not yet a global currency, but I think we can say Bitcoin is on the way for this.
Bitcoin can be called a global currency in the sense that it is usable in any corner of the world, but in not the sense as you said of being used by all the world because we are still too far away from that, we are still not even 5% of world's population, so for becoming global in that sense, we still need years.
I agree with you. Bitcoin has the potential to become a global currency, but it's not yet, less than 2% world population use bitcoins yet, it's too little amount of persons using bitcoins. To be global currency this number should be higher.
When the economy starts working properly and bitcoin be used as normal currency and not only to make profit holding, trading, gambling, it will be a global currency and of course, when more persons around the world start using it.