Silly author didn't take time to measure on X11, instead 'KDE drops it' author could use older version of KDE or SonicDE fork (rebranded KDE and only X11 support). And while on X11 i'm intresting how XLibre would fare in this metric, because git master of this project feels very snappy.
Wayland is better if you have multiple monitors with high DPI and different fractional scaling settings. But yes, it is less functional than X11 in other ways.