Shouldn't we say that the price of fiat is interest rates?
You could say that the price of bitcoin could also be interest rate as loans under sound money won't disappear but there has to be a difference since fiat is *nothing more* than that interest rate.
Also, the highest form of money, I think, can only be measured in goods and services. You could say that a US dollar price is 2 canadien dollar but that statement is meaningless if we don't know the price of 1 us dollar in bananas to begin with.
The highest form of money cannot have a price outside every single individual human mind based on their particular situation.
(I'm confused myself in all this, it might not be clear)