It's a subject that's been brought up a few times, and eventually we were told that they didn't have anything currently planned for it at all.

Assuming this is still the case, there's no harm in discussing ideas that you think would be a good use of the currency. Let's hear them.

Personally, I think it should be something as simple as letting us exchange the currency for Grand Company marks.

As it stands, we have seven types of currency.

Amalj'aa, Ixali, Kobold, Sylph, Sahagin (not currently obtainable, but in the files), Goblin, and Qiqirin.

You could break most of those down into specific regions based on beastmen that inhabit the regions, as well as materials that would seem "useful" to the companies lore-wise.

Amalj'aa and Qiqirin currency could be exchanged with the Immortal Flames.
Kobold and Sahagin could be exchanged with the Maelstrom.
Sylph and Ixali could be exchanged with the Twin Adders.
Goblin cogs could be a universal currency, exchangeable at all companies.

It wouldn't have to be anything huge, either. There are currently three tiers of currency, so each could have a scaling amount of marks rewarded.

Tier 1 currency: 5 Grand Company seals per coin
Tier 2 currency: 20 Grand Company seals per coin
Tier 3 currency: 50 Grand Company seals per coin