Earlier quoted context omitted.
Maybe it's because when you set fractional scaling you lose pixel perfect design (icons, images, and so). https://icons8.com/articles/make-pixel-perfect-icons/
It dosen't happen that way on windows. I had scaling set to 1.25 and got no issues anywhere. The issue with linux is that X wasn't designed for this and Wayland is still unstable/unusable (thanks nvidia)
You do get scaled (and hence somewhat blurry) icons if you do 1.25x on Windows as well. 1.5x usually works better, because icons scaled by that much tend to hit the next size tier that is often available prescaled to look good (16x16 -> 24x24, 32x24 -> 48x48).