Final answer:
It's urgent they find Bilbo because he is the main protagonist in 'The Hobbit,' necessary for the dwarf-led quest's success due to his burglar skills, and central to the story's advancement and his character development.
Step-by-step explanation:
It is urgent they find Bilbo because he plays a critical role in the story as the main protagonist. Within the narrative of The Hobbit, Bilbo Baggins is sought after due to his agreement to join an adventurous quest with a group of dwarves. His unique skills as a burglar are necessary for the success of the mission, as they believe he will help them reclaim their lost treasure from a dragon. Moreover, Bilbo's journey is central to his character development and the unfolding of the plot, making his presence crucial to the progression of the story.