Which, in the end, give a cosmetic transmog set. They aren't specifically for money, level progression, character strength, or any other significant progress for your character at all. That's all a far cry from cosmetics, which have already been charged for money in the past with pets, mounts, RAF rewards (including a set, enchant, etc), cosmetic helms, character appearance change, as well as other cosmetic services (faction change, race change).
I mean, if you're predicting that they'll charge money in the shop for meaningful progression quests, paying for an entire expansion is exactly what you're afraid of anyway. You're paying for a chunk of content full of quests, a new level cap, raids, dungeons, gear, and sometimes races and classes. This is just another thing on top of all that for, once again, a transmog set at the end of a questline.