Because there are a number of existing frustrations with GNOME that can not be fixed in GNOME, because GNOME Foundation has their own specific vision, which not a lot of people like.
KDE is good but has its own flaws, and it's a different workflow
KDE is good but has its own flaws, and it's a different workflow
So, just use KDE.
it's also usually more buggy for me, so there's that.
Now, granted, you would only know that if you're a KDE wizard. So maybe Gnome defaults coincidently align better with what you like.
But in terms of functionality, there just isn't any contest.
Not having random Z-index order bugs is also a big one