At that weight, it's personal preference. You will be light enough that you do not need to use it. Try it; if it feels more comfortable to you, then go with it. An oversimplification, but essentially what happens is your line pressure is increased to the transmission, engine mapping/throttle is relaxed, and up shifts are longer(allows more rpm, and will hold a gear longer). Downshifts are quicker and more noticeable to increase engine braking.