I read everything about the listen bus, but I didnt find how to use it as a real Listen bus, so I guess it is only usable to listen to some solo.
In Cubase you have the solo and solo safe feature, and a real Listen button that let you listen to the exact sound at the bus or track, without having the sound processed by the upward path to the main stereo out.
With that, you can listen to a drum bus, an fx bus, a compressor bus without listening to it through the whole chain after (for example compressor, eq, limiter on the master bus)