Open up the routing within the mixer and allow soft patching of inputs to any other open channel without need to unplug and re plug into another channel.
Any mix bus should also be able to be patched to any of the available outputs ie..aux outs, mono, l/r and headphone outputs.
This ability has been available on most other digital consoles on the market, ********* x32, Allen and Heath Qu mixers, sound craft etc...