Getting your song into a movie has always been good for business. If the film succeeds, the song does too. Over time, some songs become synonymous with the movies they appear in.
Vera Lynn found a new audience when her “We’ll Meet Again” was used at the end of Doctor Strangelove. As did Chuck Berry, when his “You Never Can Tell” appeared in Pulp Fiction.
The Righteous Brothers, The Doors, Audrey Hepburn, The Doors, Bob Dylan. They’ve all made songs that became synonymous with the movies they were featured in.