performance: apps are running on a subset of XOrg and xWayland translates it to Wayland
RAM: if you have no XWayland apps anymore you save RAM
features: some apps may have more features on XOrg, some may have more on Wayland. OBS on XWayland can record keystrokes, QGis on XWayland has not broken dockable toolbars.
performance: apps are running on a subset of XOrg and xWayland translates it to Wayland
"translates it to Wayland" is not correct, XWayland is an X server that runs on Wayland, not a translation layer.
RAM: if you have no XWayland apps anymore you save RAM
True. đź‘Ť
features: some apps may have more features on XOrg, some may have more on Wayland. OBS on XWayland can record keystrokes, QGis on XWayland has not broken dockable toolbars.
OBS on Wayland can record keystrokes too, it just that Global hotkeys can be problematic on KDE and requires a work around.
It does not "translate" or convert X11 windows, but rather forwards them as is over wayland input devices as Wayland surfaces to the underlying Wayland compositor.
Xwayland server still runs the same code as the regular X server, but relies on the Wayland compositor for presentation and composition of the X11 windows.
"translation" suggests conversion of X11 API calls or other code, which is not happening here.
Yes, you get the usual Wayland benefits and tighter integration with the system. However certain applicants can be a little unstable when doing certain actions.