> To bring $1 worth of US currency into existence, it only costs a fraction of that amount.
> But to bring $1 worth of bitcoin into existence, it costs $1.
But this just says the seigniorage value of creating bitcoins is 0. It doesn't say the total value of creating bitcoins is 0 -- they might continue to produce value after being created!
For example, the situation you describe applies in full to actual physical currencies. The Somali shilling trades at the (quite low) cost of printing the paper note. But the existence of the shilling still has value; it enables commerce in Somalia.
Economies operating on a basis of metal currency, or cowry shell currency, also have this feature - pretty much by definition, the trade value of the currency is mostly just the cost of producing it. (For coins, the trade value is usually slightly higher.) But every time a trade occurs, gains from trade are produced, so the currency constantly generates additional value just by being in use.