Define "post-scarcity". You can't replicate everything (without programmable matter, anyways...), and some raw materials are needed to build the replicators. And latinum is a rare commodity, though I don't know why it's so value beyond its scarcity. Greed will always be there as long as some things remain scarce yet required for a functioning society.
Yes, but beyond its scarcity, what other purpose does it have? Lots of things are rare and can't be replicated, but their value comes from the need to use them for some purpose such the ability to build other things that you wouldn't be able to build otherwise. Latinum has never been shown as anything more than a currency with nothing behind it to give it value.
In societies outside the Federation, where they don't have replicators, things have value due to being able to use them for other purposes. Latinum has never been shown to be used for any other purpose except to trade. Its not clear why a useless material is considered valuable, except for the fact that its rare.
Gold is used in a variety of applications. You're likely holding a device filled with gold right now. Even before the computer revolution, is was still used in medical applications. There are tons of uses for gold that don't involve currency.
It was shiny, easily workable, and didn't turn your skin green. As a jewelry metal, it was much more valuable than as a currency. It had uses other than just money...
Trek Club (lemmy.world)