Here we go. Coloured leads below.
Instead of reaching around the back of cabs and keyboards for endless cables, you pipe them all into the back of a patchbay. The INPUTS go in at the top, the OUTPUTS go in at the bottom. This is on the back of the case and invisible.
What you then do is patch the front of the patchbay using jack leads.
If I've got, say, a Korg synth on 12, I take the output and feed it to the input of, say, a delay unit on.... 14. I take the output from 14 (synth with delay) and patch it to channel 20 input, which is my audio interface.
No more scratching around behind cabinets, just easily plug in or out.
You can leave connections on the back permanently plugged in. Plugging something into the front panel overrides the back connection. Easy.