KDE has always favoured SSD over CSD. So it kind of makes sense that LIM was rejected.
https://blog.martin-graesslin.com/blog/2013/02/client-side-window-decorations-and-wayland/
Aesthetically, I think CSD is the way to go. But functionally, I love KDE too much to use anything else.
SSD: Server Side Decorations
CSD: Client Side Decorations
It’s how kwin fundamentally works. And why you can’t just have application specific buttons and widgets in kwin window decorations like how in Gnome you can.
The article I linked is from 2013. They’ve been discussing this for a long time.