> Nobody is saying that it is going to replace all other forms of money.
To be a money it somehow has to. What is the value of a dollar ? The set of goods you can buy with a dollar. As long as the value of a bitcoin is expressed in another currency that is weird to call it a money.
The value of every currency is expressed in other currencies. How else would you do it? Are you saying there is nothing in existence which can really be considered "money" except maybe the US dollar?
How is that different from Bitcoins? If suddenly every land on Earth but one is flooded, and some people there happen to use Bitcoins (in addition to their other assets, probably), Bitcoins will still have a value too. Same with gold and everything else besides the fiat currencies of the sank countries.
The value of a currency is expressed in purchasing power. Exchange rates are prices of currencies in terms of other currencies, they don't tell us anything about purchasing power.
Sure, the actual utility of the currency might be best measured with purchasing power and not exchange rates. Same with Bitcoin or anything else, though.
To be a money it somehow has to. What is the value of a dollar ? The set of goods you can buy with a dollar. As long as the value of a bitcoin is expressed in another currency that is weird to call it a money.