That's not particularly helpful or clear, so most players remember that rule as "take out dead cards, bring in answers." In many ways that is true, but it's not the actual point of sideboarding
[17] Spells consume mana, usually requiring at least one mana of a specific color
However, a mistranslation in the English print cut out the point of being "Active," which allowed players to stack their benches with Slowkings until they stall their opponent into defeat while shielding the Pokmon from any damage
House, President and CEO Overseer of Vault 76 Paladin Elizabeth Taggerdy Powder Ganger Ruthless Radrat Thrill-Kill Disciple Yes Man, Personal Securitron Desdemona, Freedom's Edge Keeper of the Accord Legate Lanius, Caesar's Ace Mysterious Stranger Pitiless Plunderer Rose, Cutthroat Raider Sierra, Nuka's Biggest Fan Wasteland Raider White Glove Gourmand Captain of the Watch Instant (7) Secure the Wastes Deadly Dispute Anguished Unmaking Wear / Tear Entrapment Maneuver Lethal Scheme V.A.T.S
Spell Versatility: High This impacts the board dramatically, either by delaying or effectively exiling your opponents best creature
Yes it gives your oppnent a 2/2 flying swan, but who cares
