As I remember it was for thanking the players for playing and waiting for patch 2.0
Full crafted crystal gears is considered end game things that's why it has a difficulty in attaining.
For me item progression is
Legend Equips -> Eternal Equips -> Crystal/mythic crafted gears
Getting crystal legends that gives you an affix that you want to use is pretty nice in moving forward as you don't need to rely on a obsidian.