Hmmm, the only thing that I can see as an advantage is that when you use the separate outs, the 4X master volume control only changes the KB tones, and not the vocals. If you didn't separate the two, then raising the master would also raise your vocals. You have separate control of the mic, and keys from the front panel knobs ... all except the master. Hey - what ever works for ya. If you like running the extra wires, then go for it!