Copying a value creature draws you a pile of cards, while copying a powerful threat like a Titan or a big ETB effect like Agent of Treachery can straight-up end the game
The only difference between this slots potential and the foil regular-frame rare/mythic slot is that you cant get a foil Saga here, as there are no special frames for Sagas
Can it get any simpler than that
Delirium As long as there are four or more card types among cards in your graveyard, this creature gets +2/+2, has flying, and attacks each combat if able
If left alive, it overwhelms the board quickly, and with Thornbite Staff and Skirk Prospector, it enables infinite loops that produce endless Goblins and mana, often ending the game on the spot
They introduced new mechanics and technology to enhance the gaming experience, while still staying true to the original story