UW is fantastic and is hard to go back to 16:9, but I'd say it's equal to 4KHDR, and most importantly VRR.
The jump in pixel count from a scene rendered in 1920 x 1080 vs the same scene rendered internally at 3840 x 2160, is absolutely massive and cannot be downplayed at any cost. The same goes for eliminating screen tearing, with no stutters.
In my personal opinion, VRR is most important tech in recent years for video games, because everything else were expected, natural upgrades as hardware moves forward.