Sadly, yeah. There is a big notice when you go to buy a code to not trade it for in game Gil or items.

That said, I think it is silly and they should just make it tradable naturally. RMTers gonna RMT, and I would rather se gets the profits then some third party company. Plus it would be really beneficial for people like me. I craft and vend a lot in game and have a lot of Gil, but am currently a poor college student out of game. I would love to be able to spend my Gil on fantasias and such, since it is otherwise rather hard for me to come across. When I get out of college and have a full time job it would be better, but for now I wish I could just buy them off someone for Gil.

Other large MMOs and large games offer items for sale from their cash shop (be it sub tokens or mounts or whatever)