In general, Islam does not recognize any currency that is not covered by gold, silver, and other assets.
Based on the above definition, all current currencies are not considered as money according to Islamic Sharia.
Muslim scholars in the current era added an exception to the currencies not covered by gold provided that there is a hand issued and guaranteed value such as the Central Bank.
Therefore, most Muslim scholars do not recognize bitcoin but may change in the future.
Yes, you are spot on. This shows that while the Muslims say they will not accept any decision made by world's governing bodies, International monetary system which contradicts Islamic Sharia Law but they accepted the current fiat money system which is not backed by any commodity in the 80's in most of the Muslim countries. But the following hadith says,
“Gold is to be paid for by gold, silver by silver, wheat by wheat, barley by barley, dates by dates, and salt by salt, like for like and equal for equal, payment being made hand to hand. If these classes differ, then sell as you wish if payment is made hand to hand. “
[Sahih Muslim, Book 10, Hadith 3853]
Those so called Islamic countries and their grand Islamic Scholars have also accepted Debt-based, Usury generating Central Bank backed paper money simply because the global acceptance of such paper money. What gives those paper money the value they have? They say it is the confident of people's acceptance! But is it any way allowed according to Islamic Sharia laws? No. Islam says it only allows commodity of values which price can be mesured by the scarcity, supply, demand. Now the question is, whether Bitcoin can be regarded as a digital commodity? Many people say no it is not. But in my view it is a commodity which needs to be mined and scarce too! Thousands of people are the owner of it and this means that Bitcoin is not regulated by any governing body and we see bitcoin as a medium of exchange. People are still trying to catch up with the blockchain technology and the means of cryptocurrency is yet to gain people's confidence. But here we are on this forum, every single one of us has confident in bitcoin. Bitcoin seems to me a digital currency that absolutely supports the condition of Islamic law for currency. This view is totally mine but I am looking forward to Islamic scholars view on this who will give their verdicts from a neutral Islamic and technological view which will not serve their own country's Central Bank and Government's purpose.