I don't think bitcoin will become a world currency, at least in the short term. We all know that bitcoins can be used as a way of payment, but Fiat is still the mainstream way of the world, and it's hard to get a share in the payment field without the support of national policy.
Yes without the agreement from governments in the world there is no way bitcoin will become a world currency but many governments are considering about Bitcoin to use as an international currency so we should hope for the best in the future because it decide not only the future of Bitcoin but the future of other currencies and the entire crypto market