To capture phone or video conversations.
Filmmakers often use the crosscut to show two characters talking on the phone. The camera cuts back and forth as the conversation progresses, and there’s room to play with dialogue and its relation to the action in the frame. For example, in Ferris Bueller’s Day Off, Ferris pretends to be bedridden while talking to his father on the phone, but really he’s sitting at his computer, pressuring his buddy Cameron to come over.
To build suspense.
Crosscutting can bring viewers to the edges of their seats. Think of an action hero racing to defuse a time bomb, the hero’s actions interwoven with cutaways of the ticking clock.
In The Silence of the Lambs, director Jonathan Demme uses the crosscut to build suspense, but also to misdirect the audience. By cutting from a scene of the villain Buffalo Bill at home to shots of FBI agents surrounding a house, Demme suggests that justice is about to be served. But the FBI agents break through the doors and windows only to discover that the house is empty. Buffalo Bill is in a different house, opening the door to Clarice, the protagonist, who must now face him all alone.
To make a point.
Crosscutting can also establish deeper meaning, as in the climax of Francis Ford Coppola’s The Godfather. Michael Corleone is in church, becoming godfather to his sister Connie’s daughter. Meanwhile, Corleone’s men are eliminating his rivals. The scene begins with a match cut (a juxtaposition of two frames that are thematically or compositionally similar). The first shot is a close-up of the baby in Connie’s hands. The next, a pistol in a man’s hands. Then the camera cuts back and forth from the church, where Michael renounces Satan, to the brutal murders, establishing his baptism as mafia boss.
To play with time and space.
Christopher Nolan, a master of crosscutting, uses this technique in Inception to show simultaneous action on different planes of reality. In one famous scene, the protagonist, Arthur, is asleep in a speeding van chased by men on motorcycles. Meanwhile, in his dream, Arthur fights men in a hotel hallway. When the van swerves and rolls over, gravity in the dream world swerves and rolls over. The result is one of the most suspenseful and memorable fight scenes on film.