My spouse's old GTX 1080 died, so we bought an RTX 3070 to replace it, since the Core i7-6700K system the old GPU was in could accommodate that.
The store had a great deal on a Samsung CRG9 Dual QHD (5120x1440) 49" curved 120Hz FreeSync monitor, so we figured we'd give it a try, as an upgrade from the 32" GSync monitor currently attached to the system.
My spouse is ecstatic over the result. The game runs fast, and between the high frame rates (with almost all the eye candy turned to max) and the monitor covering the entire field of view when seated in front of it, the level of immersion is addicting.
My spouse says the new setup creates a new appreciation for the hard work and artistry that the designers have put into the game: just flying around, the vistas that are encountered are much more breathtaking, and the increased visibility is advantageous in combat as well.
The only time the game doesn't accommodate the ultra-wide view is in scripted cut scenes, which are presented in a 16 by 9 ratio (versus the monitor's 32 by 9) with black bars on left and right.
So if you asked my spouse whether you should get an ultra-wide gaming monitor to play FFXIV on, the answer would be an enthusiastic "Yes!"