Well.. I don't know why you're surprised. Article you've linked says: "Enlightened Jewels and Elements will be replacing existing Legendary Jewels and Elements when upgrading the following items: Earring: Skybreak, Skypearl/Apex, Ring: Skybreak, Skyshatter/Inheritor"
Do you see GC acc listed anywhere? They did that to make lower level accessories cheaper to upgrade as they will require 2/3 less jewels in general. GC acc are still top level legendary gear so I would not expect them to be made cheaper any time soon.