unfortunately, it is traded like a metal rather than providing a long run stable store of value. and as a medium of exchange, it sucks.
is there any asset whose value one can rely on? i think they all move around.
ultimately, trust is vested in the stability and authority structures of a society. and trust is the essential element of value.
so a fiat currency can last in a robust civilisation. whereas it is unlikely to last in a corrupt one.