No matter how you implement fractional scaling, it's not going to look good. The reason is simple: half pixels don't exist. If an app wants to draw a 1px solid border, it can't draw it on a 1.5 scaled display because 1.5 pixel doesn't exist.
So your explanation, while common amongst Linux devs, is a rather cheap cop-out in comparison to the bigger two competitors who have mostly solved the problem.
The end result is that Linux DEs can be horrible to use on many HiDPI laptops, which don't have exact resolutions to make integer scaling feasable.
It is also careful with the resolutions it supports, it is not just any random scale requested. It is always to scale down, but not lose many pixels. For example, with 2560x1600 physical display (rMBP13), you can go to logical 2880x1800 (@1.78 scale) or 3360x2100 (@1.52 scale), but not further.
With Linux (and also Windows), people have weird requests that would not fly in macOS world.
Wayland works the same way.
The quick test is, when I do a screenshot, I get a file with dimensions same as physical display, not logical resolution. On macOS, it is exacly the other way.
Scaling with GPU is more flexible; you can do things per surface instead of per desktop; but slightly more complicated (because you do things per surface instead of per desktop), takes away GPU capacity/memory bandwidth from applications when then might it, and is more power hungry when the GPU could be idle.
What everyone means by "it's like macOS" is that the same "render at ceil(scale) and downscale" general principle is used.
With 2560x1440 display, you won't get fullhd@2x sized desktop (scale 133%) on Apple. That something expected in Linux or Windows, but Apple will get you at most 1680x1050@2x (152%, they're 16:10, so different height) here.
It is compounded by the issue, that Apple traditionally used 72 dpi for @1x scale, while Windows and Linux used 96 dpi. Apple apps look quite good at lower resolutions, while Linux (ok, Gnome) dug itself into a hole and looks good on dpis much higher than 96. For Apple, it is acceptable to run 2880x1900 or 3360x2100 on 2560x1600 display, but when Gnome looks passable on 1600x900@1x, good on 1920x1080@1x and you've got 2560x1440, so you need to display 4K (1920x1080@2x) logical resolution on that... that's more "interesting".
But then hit-testing it with mouse pointer is another level.
Browsers have luxuries that desktop compositor with desktop apps do not have.
The apps would have to cooperate, and that would need rewrite. In many cases, re-architecturing them.
Who is going to do that? Nobody. We need to live with the legacy that we have. How resizing non-compliant applications works (and looks), see the experimental fractional support in Mutter.
The app tells the toolkit to draw a button at 10,10 with a size of 100,20. The toolkit multiplies everything by 1.5 and then draws the button. The app doesn't need to know that this is happening at all. Of course this is not possible with some applications that do weird things, but for the 99% this works, and the 1% can just be resized by the compositor. That's exactly what Windows does.
But Windows is not a garden of roses either, I still see a fair share of blurry dialogs (until recently, even vscode installer/updater).