I think their main attraction is they cannot be manipulated and devalued by governments like fiat can. There are only a limited number of bitcoins that will ever be mined (IIUC) and therefore they have 'real' value, unlike fiat. Though you'd think they'd have top adjust the availability at some point simply due to supply and demand?
There are a number of places you can use them, OK, not many but you can exchange them for fiat. So there's not much difference in that context between bitcoins and precious metals. They're all things that we collect with the hope of reverting it back to fiat at some point.
