It was just an example of how X11 does affect performance of everything, especially on computers older than 3 or 4 years. On my computer, Gedit takes ~1.5 seconds to open after a cold boot. That's presumably because my computer is 6 years old and was "meh" when I got it but I can probably assume that it would open faster on Wayland/Mir/whatever
No announcement yet.
X.Org Security Advisory For X11 Going Back To 1993