Individual channel outs are always a post fader feed and they don’t affect the main stereo bus output. You should know this.
The output is post mic amp, post EQ and post fader. The stereo output is unaffected.
The purpose originally was to be able to take a feed from each channel to a multi-track machine and use the stereo out just as a real-time monitor. Of course, that was before the introduction of ProTools!
Nowadays, like everyone else, I record individual tracks (using my BRICK2 wherever possible!) and mix down using an old 828S, the perfect analogue mixdown.