Eh, maybe “blind faith” isn’t right, but then it wasn’t right referring to dollar bills either. Gold is worth something because people think it’s worth something, the same as with paper money. Of course you might say the value of anything is dependent on people thinking it’s worth something; but there are things that would be valuable to Robinson Crusoe (because he could eat them or use them to shelter himself from the elements, or use them to obtain other things he could eat or use to shelter himself from the elements), and gold would be pretty damned useless to Robinson Crusoe.
Comparatively recently gold has actually acquired some worth to our civilization, for various industrial uses; historically, it’s been useful for the relatively trivial purpose of ornamentation–and mainly gold has been useful as a convenient store of wealth; as money.
I don’t even think it’s advantageous to have your money be “worth something” in a practical, build-a-house-out-of-it, have-it-for-dinner sort of way. Money is just a symbol of stored value. It’s a record that Thag had so-and-so many goats and Ogg had a bunch of really good flint arrowheads, and they traded back and forth for them, even though Ogg doesn’t even really like goat-meat, because he knew that Morg likes goat, and Morg makes really good, accurate bows (to go with Ogg’s flint arrowheads) and so on and so forth.
Gold started out as just another trade good, and not even a very useful one–it wouldn’t be something you’d want in a famine (gold fishhooks or gold arrowheads being pretty impractical)–but it did turn out to be very useful as tangible symbol of stored wealth, an abstraction made real (due to its durability and workability by people with comparatively primitive technology and Goldilocks sort of rarity–it’s not too common but not completely unobtainable either). Over the millennia, this primary use of gold as a convenient symbol of stored value has so permeated our consciousness that many people the world over think gold really is money, to the point where they’ll give you food for it in anything short of a famine, and where they’ll still give you useful goods and services for it even in times of war or chaos.
But–to the extent that “instrinsic value” even has any meaning at all–the “intrinsic value” of gold is fairly minimal.