For my father it's a Range Rover he can't afford but can show people.
For me it's solving a problem (intellectual wealth).
For him, it's the promise of exchanging some electronic fairy dust for a different kind.
(all money on this scale is fairy dust and promises which scares me away from it all)
We who are working on start-ups of various kinds, seek wealth for ourselves perhaps but certainly if we are successful to increase the total wealth of the world.
At least the fairy dust of the dollar or euro is backed by the wealth of nations.
A short peek at history will show you that.
Serious question: Could a 'crypto-currency' run on a gold standard? IE MtGox (or whoever) having enough of an actual thing to cover all of the coins? I hadn't thought about that but it is an interesting thought to me.
I'd assume it would be possible to have a cryptocurrency where a central authority stores gold/dollars/etc, and allows people to exchange it for coins and vice versa - basically, have special transactions that can create coins. Miners would have to mine for transaction fees, or maybe they could be paid out of the interest produced by the giant money pile.
It would require a lot of trust in the central authority - and once you have that trust, it's not clear you need a cryptocurrency at all.