No. It is people who decided that gold is worth something for them. And it is the same way with bitcoin - people are deciding how much they want to pay for it.
Bitcoin is backed by people trust in blockchain ledger and strength of Bitcoin network, no central authority is required in our system.
And of course 1 bitcoin is worth more in certain countries and less in others - that is how purchasing power of FIAT works.
The price of gold is determined on a market that is open to the public for trade. Many people believe that gold is a vehicle for preserving USD when the dollar falls in value against other country's currencies. That part, the relative value of the USD, can be influenced by the central bank.
Gold is in exactly the same asset class as bitcoins; it's a currency derivative because it gets all of its perceived value from its USD price. You buy gold specifically because you believe it is worth a certain amount of USD, same as with bitcoins. Nobody buys a bitcoin or a bar of gold for the sake of owning either - they buy them with the intent of later selling for a greater amount of USD than what they paid to buy.
The blockchain does not establish value because it does not represent productivity. You want me to build you a barn...how many bitcoins will you off me if no other currencies existed and we had no bitcoin-to-whatever exchange? How many bitcoins would you sell me a nice condo in NYC for? Where in the blockchain will you find the answer to determine how many bitcoins is appropriate for either of those transactions?