Where were all of you angry people the past few months they've been talking about this? If you had made a stink then, it might not have been implemented, and yet you just ignored it. Typical.
Also to the genius who... apparently bought a second account to play his windows version with the steam controller, you can simply add the game as an external program and it works fine. I literally just did it. And no, I do not nor have I ever owned XIV on Steam. I logged in with my Windows account.
How to add non-steam game:
https://i.imgur.com/fTIBgZf.png
What it looks like in library:
https://i.imgur.com/IIFWvba.png
Proof and overlay and controller settings work:
https://i.imgur.com/U49POXW.png
Geez you guys... a second of trying instead of hours of raging.