A cheap creature that makes a Clue is pretty good, especially in blue, which makes better use of a random artifact token than whiteafter all, blue gets effects like Urza, Lord High Artificer and Lonis, Cryptozoologist
It has that double-faced card's characteristics in all zones
Not only that, but when a ninja - which they are - deals combat damage to an opponent, you get to reveal the top card of your library, put it into your hand and then each opponent loses life equal to that cards mana value
Many cards break into the 3-figures if they're not printed enough, like Power Artifact, and its not uncommon to get into 4, 5, and even 6-figure price ranges for the ultra-rare
Oh, and not to mention the need for recursion
Proper Storage Techniques To extend the lifespan of your card sleeves and keep your cards in top condition, store them in a cool, dry place away from direct sunlight