As I said, the whole reason they are in Job Gear at all is because they want Iconic gear for the trailer. They want people to look and go: That's a White Mage, That's a Black mage, etc.
I firmly believe that it was simply a marketing tool, as opposed to anything relating to the lore.
But wouldn't the same effect have worked if they provided the pvp gear they have? say the ilvl100 things?