This example can be similarly used in music to key the instrumental bus in a mix from the primary vocal, allowing the main vocal to sit more clearly above the instruments.
This technique is also regularly used in radio to duck the music when a DJ is speaking over it. You could have a single long drone and create a rhythm in it by using gain reduction from a sidechain rhythm, which you needn’t even send to the mix bus at all. In the example of a bass synth keyed from a kick drum, the gain reduction will follow the shape of the kick drum. In this situation, the audio signal will be reduced in gain whenever the sidechain signal goes above the threshold, rather than in response to its own level.
However, in some compressors, such as the Dyn3 used in this workshop, you can use an external sidechain fed from a completely unrelated signal.