The worldwide economy is worse than the numbers suggest and people need fiat to pay the bills.
If they use fiat, they could never payback the bills
Each fiat dollar is backed by a equal amount of debt, when they get 100 dollar to pay the bill, they created a 100 dollar's debt to be paid somewhere else in the society, plus interest. So someone else might get a 103 dollar bill to pay, society as a whole become more and more debt laiden