>>31486745I'm guessing because it's a creature that's so heavily associated with the mascot legendaries in some form or fashion that it constitutes as a "fully realized" or "higher tier" legendary as opposed to stuff like the regis, genies, etc. also similar to Phione and Manaphy. Knowing Game Freak/TPCi, I can see them issuing something as strange as this, despite how pointless it is.
