Shmoop thinks there are little pieces of a ghost story buried in this poem. They don't always jump out at you at first, but spooky, scary moments are sprinkled throughout. These help add to the tension and the excitement of the poem, and they also make the poem much more interesting than a straight history lesson.
The supernatural elements of "Paul Revere's Ride" provide a tension and excitement that gives shape and determination to the history.
The history in the poem offers an excuse for Longfellow to explore natural and supernatural ideas.