This is because, for one mana, Karn can be used to convert one of your noncreature artifacts into a creature until the end of the turn, with that artifact's power and toughness being equal to its mana value
Animate Dead is not the wordiest card, but its a card weve seen printed in three different frames, and its pretty obvious whenever anyone looks at it that the card is extremely complicated
Furthermore, many creatures in the precon deck do not have a power of 1, pressuring you to activate Offspring for each creature you cast
Then, during the player's upkeep step, they lose life equal to the number of burden counters on The One Ring
Again, you're free to look at them at any time
As painful as that may be, there are cards you can run to help you bypass these minor upsets by manipulating the cards you draw