My GPU can't push 1440 at 144hz in Overwatch, but in motion at 144hz I effectively can't see the drop in image quality that 75% renderscale causes at a normal viewing distance. I have to stop to be able to notice it.
If I'd sprung for G-sync it would be running around 110 fps and I wouldn't have to worry about it. This is on a GTX 1070 btw.
Higher res is important for some things(MOAR BLENDER PANELS), but when it comes to first-person action games(compared to say, top-down MoBA games) the high framerate is importanter.