I use the VCA tracks slightly differently. I tend to have the individual tracks EQ'd, perhaps with some dynamics and different reverbs, plus panned appropriately. My kind of stuff means that I'll have maybe 20-30 tracks - I'll probably have 6 or 7 drum tracks - but also blocks of woodwinds, brass and strings. When I'm mixing, I've got a nice balance between say the violin1 ,violin2, violas, cellos and basses - plus sometimes different articulations - so maybe some scratchy stuff and tremolo strings. All balanced together sounding nice - BUT - at various points in the song, I want to mover that cluster of faders up and down together - retaining the balance of the section. In Cubase, you just highlight the tracks in that cluster, then allocate them to a VCA group. A new fader appears, and pushing the fader up or down, physically moves the faders in the selected tracks. Very handy. No audio routing of any kind - just an extra fader that can move all the individual faders up or down together. Groups are similar - but take the audio from each channel, as balanced by the Pan control, and sum these into a shared fader that has audio running through it - which means you can slap overall reverb onto it to process the entire number of channels grouped to it. On live sound mixers, VCAs are very useful for the same reasons. Lots of novices can't work out why they cannot insert dynamics and eq onto VCAs - as they seem to do pretty much the same as groups. I just treat VCAs as remote controls for other faders.