The thing is cpu's are tested at low resolutions to show the difference, but if cpu x is stronger than cpu y that will be reflected at higher resolutions, even if the difference is smaller.
Also don't underestimate average fps with the lows too. That can make a massive difference to smoothness.
All of that aside though, can no one see the value in a cheap cpu being as good if not better than one which is nearly £800 for gaming?
There will be appeal to people already on AMD who want a cheap upgrade.
Of course overall the 12900k is better, you could argue buying a cheap 5800X would be a better buy than the 5800X3D. But for someone that only cares about gaming? Why spend more.