I use this in conjunction with my X32 Rack, the reason I opted for the SD8 - 8 channel input version rather than the SD16 was because both units have 8 Outputs and i needed more outputs for 'Front Fills, Delay speakers, Subs, Stereo IEM mixes, etc' more than i needed 16 additional inputs (although they wouldnt hurt).
On the stage, I place my X32 Rack near the drummer where all the drum mic signal cable, backline signals (such as guitar amps, bass di line) and Wireless mics go directly into the X32 Rack. and it also outputs to the Wireless IEMS and drummer mini mixer for monitoring.
and meanwhile the SD8 takes in Signals from The wired vocal mics in the front end of stage, acoustic guitar plugs right into the Hi-z input, and all the floor wedges(4units) are outputed from the SD8 aswell as Main LR, Subs and Front Fills Speakers.
And this makes only 1 Cat6 cable going from the front side of the stage to the back side of the stage. Neat, the inner OCD in me is happy!