I've always been curious as to why latinum is so valuable. Gold and silver are valuable because they can be made into jewelery. Money used to be valuable because it was tied to a gold standard, now it is valuable cause...well, cause we say it is.
Is latinum like gold or silver, something that can be made into a Giffen good, or is it tinkerbell money like dollars: Money that dies if we stop believing in it? I think in a few cases I've heard people refer to 'Latinum earrings', so I would guess the former.
That's one possible theory (Though it can't explain why the latinum didn't die in Morn's stomach, unless he swallowed a bunch of gold as well), but remember there are other things that can't be replicated as well. Dilithium, for example. And for some reason Deuterium, although that's stupid as it's just freaking hydrogen with a neutron (Come on Voyager writers, make up better fake science).