Pace, Rhythm and Timing

"Pacing refers to the rate at which cuts occur, as in how often per second or minute or hour. This is not just another way of saying 'duration of shots'"
Everything has a rhythm, pace and timing. Speech, music and film all have a natural flow.
Music is made up of beats, editing to music is one of the easiest ways to edit, and makes it look smooth and really professional by cutting to the beats, a scene with only dialogue requires much more thought.

https://www.youtube.com/watch?v=NzfSLgWkTlY

The Bourne Supremacy car chase scene is a perfect example of how fast paced editing can work really well within films. During this scene the viewer is supposed to be really engrossed into the film, and barely be able to take their eyes off of it, the usage of fast paced cuts between the cars on the road, the close ups of the characters faces and other pieces of action make sure the viewer isn't able to take his/her eyes off the screen.

https://www.youtube.com/watch?v=0bB3jFOgFTE

This walk in the desert scene is very different, there is no pace and no cuts whatsoever, just one shot following two characters walking along the desert. They are both tired, lack energy and are struggling to survive, the lack of paced editing within the scene emphasises this, where as if this scene consisted of multiple shots with quite quick editing, the audience wouldn't get the same feel from the scene.

Both very different styles of editing, both very effective.