Why graphical mods are bad for PvP.

[CaptainLagbeard]

Yeah, but if you were a sniper in a FPS game and you relied on being hidden, knowing that someone out there could alter your character to be bright green would heavily reduce your chances of staying hidden. Again, that's a FPS game and not FFXIV, but it's an example. Just because you don't look green on your screen doesn't mean your enemy can't use that to their advantage.

In an FPS game, yes that would very much be an advantage...
But this is not an FPS game, you generally wouldn't have a big name hovering over the sniper telling you they're there.

As stated by kamenkuro, the only way to not have the class name sticking out there is to be a Ninja and use Hide.