Noise gates are predominantly used in genres that use a lot of gain – because with gain comes noise! Even the best high-gain pedals and amplifiers will introduce a certain amount of noise into your sound. When you’re playing, this is masked. However, in quieter moments where you may not be playing, this can be unbearable.
If you play exclusively clean tones with lots of dynamic moments, then a noise gate probably won’t be something you use regularly. That said, there are instances where a noise gate might be helpful. Gated reverb is the use of a noise gate after a reverb effect, which abruptly cuts off a reverb tail. This can give a unique sound effect of a large reverb with a short tail – think of the drums on ‘In The Air Tonight’ by Phil Collins. As an effect, it’s more commonly used on percussion instruments but can also be used on guitar, particularly in a band environment if you don’t want your reverb to spill over into quiet sections where reverb trails may interfere with compositional moments – a musical ‘stop’ for example, where there’s a deliberate moment of silence.