What ultimately determines the value (price) of a currency is what it can be bought.
If I will sell you and ounce of gold for 16,000 BTC, I make an offer to sell. If you buy at that price there is real exchange value established.
However, past performance can only establish an expected value. If a million people buy gold for 16,000 BTC prices are well established. But tomorrow, who knows.
Maybe I ran out of gold, maybe no one wants anymore gold.
The Market merely tends to find what people see as fair value. It tends to average over the millions of transactions no matter what the currency.
In the end the buyer is sovereign in a free market. The buyer decides to buy or not. In the end the individual chooses what price he or she will pay. The individual is Lord in a free market.
We use money or currencies as a tool to communicate, or haggle for the best deal between the buyer and seller.
Free includes debt-free!