This is useful in two ways: First, if your opponent just searched for a specific powerful card from their deck, you can make sure they cant use it against you
Again, if youre after a land that draws cards, go for Horizon Canopy or Nurturing Peatland
Its effects are negated, also it cannot declare an attack this turn

Aang, A Lot to Learn Ajani, Sleeper Agent Ajani, the Greathearted Alenni, Brood Recruiter Alert Heedbonder Aragorn and Arwen, Wed Aragorn, Company Leader Archon of Valor's Reach Assure // Assemble Assure // Assemble Byrke, Long Ear of the Law Charging Troll Citadel Castellan Conclave Cavalier Conclave Guildmage Danitha, New Benalia's Light Dawnhart Wardens Earth Kingdom Soldier Engineered Might Faeburrow Elder Faithful Watchdog Finneas, Ace Archer Frondland Felidar Guardian of Vitu-Ghazi Huatli's Raptor Jenson Carthalion, Druid Exile Kaheera, the Orphanguard Krond the Dawn-Clad Murasa Rootgrazer Risen Sanctuary Rosemane Centaur Safehold Duo Selesnya Charm Selvala, Eager Trailblazer She-Hulk, Attorney-at-Law Silk, Web Weaver Spider-Man, To the Rescue Steward of Valeron Trostani's Summoner Trostani, Three Whispers Vernadi Shieldmate Veteran Warleader White Lotus Reinforcements Wilt-Leaf Cavaliers Wylie Duke, Atiin Hero Yannik, Scavenging Sentinel

40 damage and discarding a Tool is nothing to shake a stick at, especially on a starter Pokemon that you will only attack with once or twice at most in a game before it becomes useless