You are wrong.

Art holds value, although many don't recognize that (remember that for some a banana duct-taped to a wall is art, remember how expensive is an original painting, when a copy looks just as good). And it's not at all easy to exchange.
Imho gold is so expensive not because its utility, but because of its scarcity and for being hoarded.
In the history people have been using shells basically in the same way as (gold) coins or bitcoin.

You seem to be praising the modern money. You know that it's only printed paper (or whatever) that has value only because the central bank of your country says so. I won't insist on the fact that they're lying and because of inflation the value you're paying for that paper (i.e. work done) is not the same as the value you receive for that paper when you spend it. But what if your country's central bank, for various reasons, cannot honor its word? I know, it's not very likely, but imho it proves my point:

something holds value if you and a big enough number of other people sees it as valuable.

As simple as that. And yeah, Bitcoin meets this condition.