They're called "FFXIV Coins" and will be required to buy any optional items from the game's Mog Station or Final Fantasy 14 Online Store - whether that be cosmetic items, mounts, minions, dye, ...
The FFXIV Coins can be purchased from the Microsoft Store and will be used for service fees and optional item purchases ... FFXIV coins will be needed for players who want to use the Mog Station or ...