Certainly if you get to lay him and calm the board with just a +2 then you are going to win if they don't have spot removal for him
The sacrifice ability occasionally came in handy, guarding against mass removal even though it was never the primary motivating factor, and it was hard for decks running him to justify keeping the necessary mana untapped until very late in the game

Hallar, Kicker Tribal Hallar, the Firefletcher | Illustration by Bram Sels Commander (1) Creatures (16) Birds of Paradise Boreal Druid Chandra's Incinerator Dragonborn Champion Elvish Mystic Emblazoned Golem Flametongue Yearling Fyndhorn Elves Gilded Goose Goblin Anarchomancer Goblin Bushwhacker Joraga Warcaller Kediss, Emberclaw Familiar Llanowar Elves Magus of the Wheel Skitter of Lizards Instants (19) Comet Storm Deflecting Swat Falling Timber Heroic Intervention Hunter's Insight Inscription of Abundance Invigorating Surge Kazuul's Fury Nature's Claim Overload Return of the Wildspeaker Scorching Lava Snakeskin Veil Solidarity of Heroes Strength of the Tajuru Tibalt's Trickery Unstable Footing Valakut Awakening Vines of Vastwood Sorceries (13) Canopy Surge Galvanic Relay Grow from the Ashes Ignite the Future Jeska's Will Light Up the Stage Molten Disaster Primal Growth Reclaim the Wastes Rishkar's Expertise Savage Offensive Visions of Dominance Wheel of Misfortune Enchantments (13) Alpha Authority Bear Umbra Cindervines Fiery Emancipation Gratuitous Violence Hardened Scales Hydra's Growth Keen Sense Mark of Sakiko Quest for Pure Flame Snake Umbra Utopia Sprawl Wild Growth Artifacts (3) Everflowing Chalice Fractal Harness Sol Ring Lands (35) Bloodstained Mire Command Tower Copperline Gorge Cragcrown Pathway Fire-Lit Thicket Forest x12 Game Trail Grove of the Burnwillows Karplusan Forest Mossfire Valley Mountain x6 Prismatic Vista Rootbound Crag Scavenger Grounds Spire Garden Stomping Ground Windswept Heath Witch's Clinic Yavimaya, Cradle of Growth I toyed around with Hallar, the Firefletcher with the release of Dominaria and was blown away by how good it was

2 Oversized, double-sided battleground cards
Equip only as a sorcery.) Artifact - Equipment Color tag templates(None) Teferi's Protection Until your next turn, your life total can't change and you gain protection from everything
Scion of the Ur-Dragon is a five mana WURBG 4/4 Dragon with flying that is great for either casual play or silly combos