2006 jeep grand cherokee laredo pkumux

I just ordered a PKUMUX to install in my Jeep with an RS-3A remote starter and I'm reading up before the install. I'm guessing it will work fine following the install guide but I'm confused about the mux wire. From what I can tell, this wire is a combined start/ignition wire when shorted to ground through 180/560 ohm resistor (which the pkumux will take care of). The PKUMUX install guide shows the mux connection as well as connections to dedicated separate starter and ignition wires. This seems redundant. Why does the vehicle need both connections? What is the purpose of the mux wire? I thought it was a way of cutting down on the number of wires in the vehicle by combining multiple functions into one wire. I know some jeeps don't have a separate starter wire but mine does.

It is not redundant as that wire functions as keysense, accessory and second starter...all in a single 18ga (maybe smaller) wire. The 06 has a standard starter wire, but later years this was eliminated with this wire too. Installer, IT support, and FFL. I need less hobbies.