Overall you want to think of cycling cadence relative to performance similar to how you think of as engine rpms to performance in car racing.
Therefore, high cadence is best used to attack or accelerate
Most people think high power is the most critical component of an acceleration or an attack. While high power is part of it, it is the high cadence that really makes the acceleration effective.
For optimal performance accelerating, use high cadence when launching an attack, closing a gap, or raising the speed up.