Like most Magic: The Gathering cards, the value of Altar Ibn-La'Ahad depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Assassin's Creed)
At least when the pressures on attacking, it fits reds desire for aggro, but as printed it gives the red player near complete control over the combat phase, offensively or defensively
To help you survive this adventure, you are given a magical cassette tape player that records a monster and allows you to transform into the very same monsters you are fighting against
Then, when the time is right, you start casting all of your spells, allowing a bunch of them to get countered
(That player looks at the top two cards of their library, then puts one onto the battlefield face down as a 2/2 creature and the other into their graveyard