First review for this card. Although the flavor text seems to strongly scream for "Rohan!", Burst into Song instead calls for a hobbit deck that would include Sam Gamgee and/or ( MotK) Rosie Cotton, several copies of Song of Hope and Fireside Song, Red Book of Westmarch, and Steward of Gondor.
Burst into Song does not replace Fast Hitch, nor Unexpected Courage, but complements them by occasionally increasing the versatility of heroes in the face of encounter cards that would often require exhausting the characters.
This is an event that also makes the integration of Song cards into the deck more profitable or viable by reducing the opportunity cost of having sacrificed several deck slots for these cards. As such, Forth, The Three Hunters! and a possibly different Song attachment provided for each hero (for example Song of Mocking, Song of Healing, Song of Hope, or attachments of access to other spheres Song of Travel, Song of Battle, Song of Wisdom, Song of Kings), can provide a good opportunity to add Burst into Song to the deck and trigger it around mid-game.