It forces every single DE that will use it to reinvent same thing. There is no good reason to do that, just a lot of duplicated effort. You will not want to have different mouse behaviour when you use different WM. Having it pluggable is fine, even desired, but pushing it on every DE is just waste of effort and just bumps the bar required for any DE to move to wayland.
> GNOME is probably worst DE imaginable. After 20 years, they still don't have thumbnails in filepicker and even dropped preview side pane in GTK4. I can't even.
For me it peaked somewhere in 1.x, 2.x was prettier version of it, after that they completely lost me. And their constant dumb arrogance with assuming what their users want is just cherry on cake of shit. And the "fuck the compatibility, just change APIs will nilly" attitude they got after 2.x