The dance number that seems to accompany it with all the lamplighters is also wondrous, and exactly what you would want to see from Lin-Manuel Miranda in this particular movie.
Jack is an optimistic character and that comes through in the infectiously upbeat tune about shining brighter than the troubles that are getting you down.
Jack the Lamplighter is a friend of Mary Poppins, and assists her when she returns to help the Banks family find joy again during a difficult time in their lives.