Group/FX Tracks can be selected as audio input buses from Audio Tracks (which you can then enable input monitoring on to route through). Is there any technical reason why the same feature is not available for VSTi (track or rack) audio outputs?
Motivating use case: before mixing, it’s helpful to “print” virtual instrument outputs to audio tracks (whether through Render in Place or batch Export Audio Mixdown). I’d like to be able to use audio sends and effects on virtual instrument outputs while composing but then print the dry audio to audio tracks, keeping the same insert effects, sends, routing, etc.
A convenient way to do that (which is possible in some other DAWs) would be to set up matching audio tracks for each VSTi audio output and select the corresponding VSTi output as the input to each audio track (with input monitoring enabled). That way, I could use configure insert effects, sends, etc. on those audio tracks, and the exact same processing would stay in place once I printed down to audio.
To achieve this in Cubase today, for every VSTi audio output, I’d have to create both a corresponding audio track and group track. In very large orchestral templates, the added complexity and overhead there is likely not worth it.