I really have no other plausible explanation how they could miss so many potential usecases while rebuilding the display management ground-up: screen sharing, fractional scaling, different scaling factor for different screens, color profiles, HDR, toolbars and docking, window positions, and whatever else.
In the Wayland GitLab, there are comments in the spirit of "who would ever want to use this?" for a feature requests of something present in literally any sane WM...