Mostly, it's designed to slip a little when you drive the truck over rough surfaces, jumps, wheelies and the tires leave the ground, then recontact. If you run it over a grass covered field at high speed, this is a perfect example. As you run your truck, you'll see the tires "grow" at times from losing grip and the drivetrain freewheels. Upon landing again, the sudden grip is a shock to the drivetrain. A properly adjusted slipper clutch will slip a little, absorbing/eleviating the shock from traveling through the drivetrain, and into parts that would eventually fail, break or both. Like plastic drive shafts.....gears....etc.
If adjusted too loose, it'll slip and burn up the pads.
Adjust it too tight, and the torque energy will eventually break things.
It took me a little, but I finally found a happy medium and a good setting for my vehicles.