Imagine youre a new player and you open a random pack of Shadows Over Innistrad
Putting a +1/+1 counter on creatures every turn usually turns the tide in your favor, and this effect snowballs because it allows you to continue to attack and grow your guys
In design, one of the maxims is Less Is More meaning that design strives to accomplish as much as it can with as little as it can
Not that it is so difficult to kill, but if this is in play in Modern, a Red Deck is more-or-less obligated to pay the tax or it cannot win
Otherwise, you'll be needing to find ways to deal damage each turn through combat or burn spells, which is much less efficient
Retreat: C Weakness: W Resistance: None ------------------------------------------------------------------------------ Magmar D13 - Uncommon Type: Fire Evolution: Basic Pokemon Level: 31 HP: 70 R - Smokescreen (10) Effect: If the Defending Pokemon tries to attack during your opponent's next turn, your opponent flips a coin