A Control Strategy is a plan for winning a Duel by limiting the moves your opponent can make. "Spell Canceller" is an Effect Monster that prohibits both players from using Spell Cards, which works well in any Control Strategy.
You make it work to your advantage by constructing your Decks with only Trap Cards and Effect Monsters, so "Spell Canceller" will have no negative effect on you, but limit one whole type of card for your opponent.