No, I’m fine with those rewards being locked behind casual content.
You could lock them behind reputations, world quest achievements and collections, or pet battles.
They could even be normal dungeon rewards, locked behind a currency for example.
I just think that a specific item should be granted for doing a specific activity.
As I said, dumping a bunch of cosmetics behind an NPC that just says “go play the game” is very lazy in my opinion.