Why no XP gain from core game is counting towards Addons-masteries ? Make Dungeons for Addons

[Vladimir.5709]

Dear Community and Devs,

I am wondering why no XP gain from core game is counting towards Addons after level 80 ? It ruins exploration and node gathering in core game zones - no XP rewards for those. Also Addons need similar Dungeons like in core game, at least one per Expansion - would be much faster to get XP for Masteries instead of tedious event grind - Dungeons give 70 % XP per level, thats almost one Foliant of Knowledge.