This card can be seen as an alternative to using "Cursed Seal of the Forbidden Spell", as it has a higher (but less specific) discard cost for a similar effect. The downside to using this card is that it is still possible for your opponent to recover one of the lost spell cards and use it again, which is not an issue with "Cursed Seal".
Regardless of the above problem, this card can still wreck an opponent's strategy entirely if you use it at the right opportunity. An Elemental Hero deck will be all but helpless without copies of "Polymerization", for example, and a Gravekeeper's deck will be hamstrung without "Necrovalley".
This is ideal for a Macro Deck, especially against those other decks that uses multiple copies of a single spell card, as this will send a total of 6 cards to the removed from play zone (3 spells from your opponent, 2 cards from your hand, and this card itself) when "Macro Cosmos" is in play. Discard cost is all but non-existent, since you can discard either monsters to power up other cards, such as "Gren Maju Da Eiza", "D.D. Scout Plane" to gain a quick tribute, or a few strong monsters to later revive through "Return from the Different Dimension". As the opponent's spell cards are removed from play, it will essentially render them useless for the remainder of the duel, severely crippling your opponent.
It is recommended you use this card in your second (and possibly third) duel in a match. This way you can figure key cards used in their strategies and use this card effectively.