No it’s not, it’s just people like to claim it is for bragging rights. If you’re invested enough in the game to play HC you very likely already know the few sketchy areas and quests of the miniscule vanilla world and how to best avoid possible threats. I mean this is not a Souls game or some ridiculous max-difficulty Mario Maker content that requires 2000 hours to learn. It’s literally VANILLA WOW where you are clicky clicky selecting a mob and it comes running to you and you 2 autoattack it out, for the most part.
You know to not do Kurzens cave until overleveled. You know to not stand with your back to the hole in the darkshore mushroom cave or you’ll get knocked down. You know to not go on the pirate ships in STV cause the mobs aggro through the stair and wall. etc.
Everyone can grind on green mobs to get 3-4 levels on a questing zone. You can fool yourself, but not everyone else.