>>36580831They couldn't give him a Mega because the Executives didn't want him having that kind of power when they'd have to worry about writing a "good" reason for getting rid of the Pokemon, the Mega Stone AND the Mega Accessory, so they made a loophole with a special snowflake "not a mega but functionally identical aside from the trigger" form instead so all they'd have to do is get rid of the Pokemon.
Only to then proceed to give him access to Z-Moves so they now have to make up an excuse for why he's going to ditch his Z-Power Ring and Z-Crystals.