Set Age and Availability Old card sets become scarce once printing stops
FromTheShire: 5 mana mass exile is never boring in my book, that's a great rate for permanently dealing with a board and this can even once in a while happen to clip a Spacecraft as well

Angler's Shield Armor Wars Armorcraft Judge Become the Avalanche Biorganic Carapace Blessing of Frost Braided Quipu Chromatic Orrery Cloud, Ex-SOLDIER Collective Unconscious Coveted Falcon Distant Melody Duskana, the Rage Mother Earthshaker Dreadmaw Edgar, King of Figaro Flow of Ideas Flow of Knowledge Freyalise, Llanowar's Fury Gamma Grotesque Golden Ratio Goliath, Mass Manipulator Guild Summit Harmonized Crescendo Heirloom Epic Honden of Seeing Winds Infinite Guideline Station Inspiring Call Jackdaw Kaito, Bane of Nightmares Keruga, the Macrosage Last Stand Lunar Insight Mass Appeal Minas Tirith Garrison Mondo Gecko Moonveil Regent Mouth // Feed Mouth // Feed Myojin of Seeing Winds Nexus Mentality Night of the Flying Merfolk (playtest) Paradoxical Outcome Plagon, Lord of the Beach Pol Jamaar, Illusionist Regal Force Ribbons of the Reikai Riptide Director Sage's Reverie Scroll of Isildur Sea Gate Loremaster Shaman of the Great Hunt Shamanic Revelation Slate of Ancestry Soul of Ravnica Staff of Eden, Vault's Key Swordsman's Steel Tazeem The Horus Heresy The Spirit Oasis Tishana, Voice of Thunder Titan of Littjara Titan of Littjara Vivien's Stampede Voja, Jaws of the Conclave Volo, Itinerant Scholar Winged Portent

In that case, the instant spell or activated ability will resolve first
Not only is it a very strong card, but it only costs 1 white mana, meaning it can easily be played at turn 1 and stay active for an entire game
If you'd like to check out full decklists for both of these Commander decks, as well as decklists for the other decks releasing April 21, check out the official post from Wizards of the Coast