Money is anything we collectively decide it is. The original idea of fiat was to increase the velocity of money. But it was/is a corruptible system and is quite broken. Crypto has faster velocity than digitized fiat and bitcoin is infinitely more sound , so we will stop using fiat. You are correct, it's just a matter of time and adoption. I'd say that fiat *was* money early on, but so were seashells and beaver pelts, salt, copper, gold and silver.