Agree. Anything could be means of exchange. if it have trust and agreement among users. Gold once was just a utility metal among Natives of Americas and not a currency. There is no any guarantee that it will not become just utility metal again.

I think there are no any substance or objects that have some absolute value as currency and in any circumstances could be means of exchange. Currency is more social phenomena than something absolute.

From the other side currency is just a tool to solve some problem, which is useful as long, as it solves that problem or problem itself exists. It is not very hard to imagine situations when there are no any need for any currency at all, since it is jut not needed or have no any sense, like, IDK, horseshoe in 21 century. If you have some advanced 3D printer working on subatomic level, something like StarTrek replicator, f.e. what is the purpose of currency will be?

Agree. Anything could be means of exchange. if it have trust and agreement among users. Gold once was just a utility metal among Natives of Americas and not a currency.

I think there are no any substance or objects that have some absolute value as currency and in any circumstances could be means of exchange. Currency is more social phenomena than something absolute.

From the other side currency is just a tool to solve some problem, which is useful as long, as it solves that problem or problem itself exists. It is not very hard to imagine situations when there are no any need for any currency at all, since it is jut not needed or have no any sense, like, IDK, horseshoe in 21 century. If you have some advanced 3D printer working on subatomic level, something like StarTrek replicator, f.e. what is the purpose of currency will be?