To me separating compressors as drum or vocal one and using them only as drum or vocal compressor is pointless in a digital world.
Whith plugins is easy to build fx chain for seconds.
For example most famous comp duo for vocal is 1176+la2a.
Non of these is vocal comp,in fact 1176 is more drum comp,la2a actually is used as limiter more than a comp...
Separated they are useful for different tasks,together they do wonderful job on vocal.
That's just one combination out of thousands useful in different situation.
I used to listen what a comps do and like to experiment with it in a fx chain.
So listen and apply what you hear,where the track benefit from it.