This is a fight implementations cannot win.
So there is demand for API. Gnome, KDE, wl-roots implement it, in the discovery phase by their unique way, so we have 3 different APIs. Then, once the requirements are known, standardization happens and every compositor implements the standard API. So far, good.
But what happens with the old, experimental APIs? Because meanwhile, there are apps, that do use them. Remove the old APIs and you will have cries on the Internets, how you break compatibility again (even if you announce deprecation plan years upfront). Do not remove them, and you have complains, that every compositor has its own API (ignoring, that there is a standardized one too, now).
So, there's no pleasing everyone. Someone will complain.
> No it does not. Pipewire does.
xdg-deskop-portal-(gnome|kde|wlr), among other things, which do include desktop-specific dialogs related to the functionality.