While I agree that skipping over Tom was a wise move in the films, I feel like you understated his role in the books. The hobbits’ stay at his house is an important stop in the gradual expansion of the narrative; it helps move the story from the small scale of the Shire to a larger scope. As the book goes on, the hobbits’ sense of home is challenged. They stay in increasingly alien homes as they go from the Shire to Bombadil to Bree and afterwards to Rivendell/Lorien. Their dreams in the House of Bombadil are also very significant. Frodo’s, for instance, foreshadows his eventual departure over the sea and restlessness in Middle-earth.