It allows the transfer case to be shifted into Neutral, which there is no button for, so that your Trac can be flat-towed behind a motorhome.
Otherwise, this can happen:
[Broken External Image]:
:bwahaha:
Seriously though, a manual tranny vehicle you can flat-tow in Neutral just fine. With an auto tranny, simply shifting into Neutral and towing it will cook your tranny in short order because the driveshaft is spinning but the fluid is not being pumped around inside the transmission and you can say goodbye to your output shaft bearing and other parts inside the tailshaft. With a 4x4 you would leave the tranny in Park and shift the t-case into Neutral. With a 4x2 you need to have some sort of driveline disconnect or towing hubs for the rear wheels.
Would it be OK to tow in neutral if you had the engine idling? I could see for short distances <50 miles or so this might be a viable option to towing the Trac.