It's against Square-Enix's Terms of Service for FFXIV, which is why it's not allowed on the RPC. Our rules are designed to be mostly compliant with the ToS, with a little more leniency in user mentions, tone, and topics. (Not to mention we're more likely to warn than ban for a number of infractions!)
The basic gist of things is that SE doesn't want IRL items of value being associated with game items of value. So as long as IRL items are obtained with IRL currencies and game items are obtained with game currencies, all is good.
This is why a SE gets iffy about say, /random raffles taking place in game to give Mog Station items, but doesn't bat an eye at in-game "casino" style events where people bet gil using /random as a game.
edit/addition: This is actually why there was a huge scandal with people buying the Eternal Bonding rings on Mog Station and selling them in-game since they were tradeable items. People were using it as a stand-in for RMT and it caused quite an issue!
The basic gist of things is that SE doesn't want IRL items of value being associated with game items of value. So as long as IRL items are obtained with IRL currencies and game items are obtained with game currencies, all is good.
This is why a SE gets iffy about say, /random raffles taking place in game to give Mog Station items, but doesn't bat an eye at in-game "casino" style events where people bet gil using /random as a game.
edit/addition: This is actually why there was a huge scandal with people buying the Eternal Bonding rings on Mog Station and selling them in-game since they were tradeable items. People were using it as a stand-in for RMT and it caused quite an issue!
