Anyone who has played a trading card game knows that drawing cards is satisfying; it often signifies the beginning of your turn and is symbolic of increasing one’s chances to do fun things. Newer players, however, may not fully understand why drawing cards is such a powerful mechanic and may not understand how the meta-game of trading cards (often called a one-for-one) and fighting over card advantage works. Put simply, card advantage is when one player has access to more cards than the other player. If a player starts off their first turn by playing an Island and then tapping it to play an Ancestral Recall, that player is at +2 card advantage. Each time you play a card, you’re decreasing the amount of cards you have available, so cards that allow you to draw additional cards can turn the invisible game of tug-of-war in your favor. Powerful cards are often those that allow a player to two-for-one, or even three-for-one their opponent, meaning that their one card took care of or in some way counteracted two or more of the other player’s cards. Playing a card like Ancestral Recall gains card advantage, but playing a Wrath of God against an opponent with a board full of creatures is also creating card advantage in one’s favor.
A cantrip is simply a card with the additional effect of drawing a card. This is usually added to cards with effects that, by themselves, would not be worth using up a slot in a 60 card (or 40 card if it’s a limited deck) deck. This allows cards with weaker effects to let a player to maintain card advantage. Cantrips are often parts of combo-decks where the act of drawing cards or casting spells is more important than the spells themselves (see the Jeskai Ascendancy combo deck, for instance). The additional draw also gives players a chance to gain better card quality.
Essentially, card quality is the y-axis to the Card Advantage x-axis on the graph that shows how good a player’s hand is. While card advantage measures the volume of cards available, card quality measures how applicably useful those cards are for that player’s specific situation. Cards that allow a player to draw cards, tutor (search one’s deck for a specific card) or scry (look at the top card of one’s library and choose whether to put it at the top or bottom) all promote card quality. One of the strongest cards, or at least card archetypes, in Standard currently is Thoughtseize, which allows a player to look at their opponent’s hand, choose a non-land card from it and discard it. If a player only took card advantage into consideration, Thoughtseize would look like an awful card, as it takes one card to get rid of one card. A one-for-one is not necessarily bad, but it does nothing for one’s card advantage. What Thoughtseize does do, however, is guarantee card quality. If a player draws 6 lands and one great card, Thoughtseize essentially cripples them. If a combo-deck relies almost entirely on drawing one card and the opponent uses Thoughtseize to get rid of it, that combo-deck player’s whole game plan is shot to hell.
Cards like Dig Through Time also exemplify the power of card quality, as it costs eight mana to draw two cards, which is absolutely horrible compared to Ancestral Recall in terms of card advantage, but allows you to choose those two cards from the top seven cards of your library. Being able to look at the top seven cards of one’s library and pick the two best ones for any specific situation is incredibly powerful and just goes to show how important card quality is in the game of Magic the Gathering.
While Card Advantage and Card Quality are not the only two barometers with which players can evaluate cards, they are very important qualities of cards that are considered very powerful. A card like Hydrosurge, is part of a notoriously bad archetype of cards that lose the casting player card advantage while not actually affecting their opponent’s access to cards. Wizards of the Coast attempted to remedy this by printing cards like Fleeting Distraction, a Cantrip version of the -X/-0 archetype, which helps the card a little, but still only really finds use in combo decks that want to cast a bunch of cheap spells, regardless of what they do. When looking at Magic cards, keep in mind how each card affects card advantage and quality, especially if a card has the potential for reducing your opponent’s card advantage greatly (through something like a four-for-one) or for increasing your own card advantage (by drawing cards). Magic is a game about cards and having access to a large amount of really useful cards is essential to playing a good match.