I strongly disagree that being ultrawide is an advantage. 16:9 is already wider than optimal for gaming. The human field of view is actually about 4:3. While there is admittedly usually more interesting content to the sides than the vertical edges, I've found 16:10 to be preferable for immersion and would never dream of going wider. If anything, I'd go closer to a square if they still made them.
I'd rather have 2560x1600 than 3440x1440, even though it's less pixels.
IMAX film format has a more immersive aspect ratio too, which is taller still at about 16:11.