Not yet, but I know that we are getting close where can claim that btc is the strongest currency. I can feel that we just need to take a few more steps before everyone around the world will use btc instead of usd. It may not be a quick transition but I know we will get there.
If we are talking about the world of crypto currency, then there is no point of denying this fact that bitcoin is the strongest currency. Otherwise, bitcoin is not the strongest currency. There are so many other regular currencies which are far better than bitcoin.
It will take lot of time for bitcoin to make its name in the ranking of regular currencies. There are likely chances of this thing to happen but it is not an easy task.