This is telling us that Bitcoin cannot do without Fiat currency but can Fiat currency can do without Bitcoin because from the beginning before you get Bitcoin you must to have flat to exchange the Bitcoin that is why I do disagree with people who says that bitcoin will take over Fiat currency in some trend I've seen so far so with combination work between Fiat and the Bitcoin they will know that the element that brings Bitcoin to be known and to be recognise is true Fiat currency and without that it can't cannot fully
what you need to ask yourself.
bitcoins "coupling" is not about coupled to fiat generally..
the actual coupling grief is the DOLLAR attachment(out of all possible fiats, why DOLLAR?!)
dollar is only used by 330m people. yet other countries like india and china have a billion + each people using their respective currencies
so why have DOLLAR as the coupling
then.. note this while thinking about 'coupling'
bitcoin CAN work without being DOLLAR coupled. heck it can work by being coupled to a non fiat measure.. such as "min wage hours" which would be a more fair coupling for all citizens of the world while disrupting wallstreet/forex
where by the price changes in measures of seconds/hours... which then later EASILY converts to their local fiat rate of their local fiat min wage number.
rather then measured in dollars/cents and then converted to their local fiat rate
anyways..
fiat will never disappear. governments will always exist and taxes to pay for social/public services will continue and governments will always want control or their value in their nation separate from another.
i know the euro has shown a sign of change where by the french government is not using the franc. but instead using a subset/ section of reserve of euro. where some think that can expand to a "one world currency"
..but there will always be rival countries that dont want to be puppets to a master single currency and also it reduces trade options if everyone were to use the same thing. as there is less swap opportunities for rivals to fight over.
forex is a business in of itself.
having bitcoin as a "one world currency" where by all countries only ever use bitcoin.. defeats the point of bitcoin.
bitcoin is a free option to hedge against fiat. its not meant to replace it. its meant as an escape door option away from fiat. if there is no other currency. there is no escape meaning bitcoin becomes as corrupt as fiat if people cant escape from it