Everyone has their one opinion on bitcoin, if you say BTC will not be the world currency in the world then no will argue with you because that is how you see or your point of view.
Yes, that's right, here everyone's opinions and views about Bitcoin are of course different, therefore someone has the right to discuss what he thinks, one of which is the discussion of Bitcoin being a world currency/this topic, and I think it's here who will read it and understand Op's statement will definitely discuss and not argue, and maybe they discuss with each other's opinions.
Bitcoin did not come to remove Fiat currency but bitcoin is here to strengthen the Fiat currencies in the world if only they understand the coin adopt it.
Going back to the original purpose of Bitcoin, it came only to form a digital currency and it is decentralized, meaning that Bitcoin will not overthrow FIAT money and I think Bitcoin will continue to coexist with FIAT currency and strengthen FIAT money, moreover the Bitcoin payment system is
peer-to-peer to-peer is decentralized and makes it easier for users to carry out fund operations/transfer funds quickly without intermediaries, in contrast to the work systems of centralized banks and financial institutions.