That can be clunky at times, seeing as dragons are expensive, and even if you land them, you may have your commander killed and lose the potential benefits
If you happen to have loads of sac lands and some discard effects then perhaps it gets there too
If another effect modifies how much damage a source would deal, including preventing some of it, the player being dealt damage or the controller of the permanent being dealt damage chooses an order in which to apply those effects
Its particularly good for nonspecific tribal decks that have multiple creature types, like Sea Creatures (Leviathan, Octopus, Serpent, etc)

Banishment Basil, Cabaretti Loudmouth Benalish Knight Benevolent Blessing Black Panther, Hope Enduring Blur of Heroism Brilliant Wings Caprichrome Captain America, Unbowed Captain Mar-Vell, Space-Born Captain Marvel, Earth's Protector Cast Out Cathar Commando Celestial Armor Celestial Crusader Cemetery Protector Champion of the Clachan Chea, Friend to Maybe Too Many (playtest) Cho-Manno's Blessing Chromium, the Mutable Cleaving Skyrider Commander Sofia Daguerre Containment Priest Dawnfluke Deep Gnome Terramancer Deepway Navigator Defender of Law Deputy of Acquittals Dictate of Heliod Dog Umbra Doorkeeper Thrull Drogskol Shieldmate Dust Elemental Elsha of the Infinite Errant and Giada Ethersworn Shieldmage Fated Clash Feather of Flight Flash Thompson, Spider-Fan Fleetfoot Panther Flock Impostor Foggy Nelson, On Retainer Force of Virtue Foriysian Interceptor Gandalf the White Gatta and Luzzu Get Your Head in the Game Gift of Granite Githzerai Monk Glamer Spinners Glorious Protector Grey Knight Paragon Guardian of Faith Guardian's Magemark

And in the face of a battlefield sweeper, you can sacrifice Bighorner Rancher to gain some life