Balefire Dragon makes connecting with one player threaten that player's whole creature board. Its combat-damage trigger deals the same amount of damage to every creature that player controls. A successful hit can therefore clear blockers for later attacks while damaging the opponent, giving red ramp and Dragon decks a combat-based way to regain control of the battlefield.
Haste is especially valuable here. Lightning Greaves or The Fire Crystal can let the Dragon attack before an opponent untaps to remove it. Power boosts increase both the player damage and the subsequent damage to creatures. Double strike can produce separate triggers when it deals damage in both combat-damage steps, though the board may change substantially after the first trigger resolves.
The trigger requires combat damage to a player. Damage to a planeswalker does not qualify, and a flying blocker can stop the trigger unless trample or another effect pushes damage through. Even after a connection, indestructible creatures can survive the damage, and prevention effects may change the result. Look for the player whose board can be profitably cleared rather than automatically attacking the lowest life total. At seven mana, Balefire Dragon should have a credible route to connecting; the strongest setup pairs the threat with immediate haste, evasion support, or removal for the blocker that would otherwise keep its main ability dormant.
