De-esser plugins are often used just to control sharp resonances in vocals.

Try rot think of them as dynamic EQ’s instead of just a vocal tool. 

You can use them to tame sibilance with all sources whether it be harsh cymbals, a peaking acid synth or even a percussion loop with some sharp tambourines for example.

The benefit of this is that it can sound more natural as it only affects the tone when the harsh peak breaches a threshold rather than a constant eq cut of the harsh frequency which will make the rest of the recording sound processed.