Its drawback may look like its very punishing and can allow the opponent to surprise you via a mid-combat spell, but I never really saw that scenario play out since its damage prevention ability is a a conditional static ability so as long as its on when damage is dealt, it wont be prevented. (Thank you, @fenaris!) It usually plays out somewhat like a colorless Ashenmoor Gouger / Chimeric Idol where you typically dont bother trying to block with it (why am I blocking with my aggro guys anyway?) and, if need be, you cast a spell pre-combat to activate it (typically I used a large coin, like a quarter, to denote whether it was on or off)
It's better than the Secret Lair drop with the line drawings
Hoarding Broodlord Assuming you can properly convoke this dragon with a decent number of creatures, Hoarding Broodlord is a universal tutor on a massive flying stick, and it even gives a blanketed convoke ability to anything you could cast from exile (including the card you just tutored)
We havent done a deep dive in a while, so thought it could be fun to do some detective work while pondering how the new abilities could change the game
Now none of these modes are particularly playable on their own, but they are all close enough to playable that this is a very exciting card