Bitcoin can indeed be an alternative universal currency replacing the dollar or other currencies that can be accepted throughout the world. But bitcoin cannot be the solution for all existing problems. Let's think rationally for fluctuations in the value of bitcoin is still a stumbling block for mass adoption. We can only predict and grope about the future of bitcoin.
Learn from the history of damage that has been caused by FIAT money on the global economy. The use of currencies that have no intrinsic value brings massive damage to the world economy. Will we repeat the same mistake by using bitcoin which has no guarantee to sustain the world economy.