There are good cosmetics, like long hard grinds, or hidden behind hard content. Things like the MoP challenge mode gear,
But right now, like 90% of the cosmetic is hidden behind useless, time-gated garbage.
I really do not care about cosmetics that much, yet the world is full with them.
Look at WQs and world content. Why would I do them? What can I gain out of them? Nothing, they do not make my character powerful.
Cosmetics are great when they test your skill, not like this crap.