Just because you know the room is safe doesn't mean the same for the players.
I have no idea where the original source image is from, so if you know, feel free to inform me in the comments below.
With great power comes great etc.
And yes, I understand that you can only transform into a creature equal to your characters level, but that simply means you let your party protect you up until the point where you could transform into a dragon.
It is just unbelievable how often the players can derail the game and still have the game turn out to be entertaining.
Your attributes will be tested by the Dungeon Master whenever they please, and you can fail rolls for Strength, Dexterity, Charisma, Wisdom, Intelligence and Constitution.
Does that mean there may be gelatinous parallelograms out there? Whoops, you're in the pain dimension now, you silly goose.
About to pick up a talisman without saying the proper words to break the enchantment? In fact, this is part of design philosophy the king of the meat-grinder dungeon, Gary Gygax himself.