Battery Grip Cable - Do I need it?

This may prove a stupid question but I am new to this game - I've just purchased a Meike Battery Grip for my D5100 - it comes with what I think is called a 'Vertical Shutter Release Cable' - first of all what is this cable for and do I need it as the rubber cover and cable sticking out of the side of my lovely D5100 is not pretty!! Can I use the grip without this cable attached? Please and many thanks

The cable is needed for using the shutter release button located on the grip for shooting portrait.
I just cut a window in the plastic cover so it will close and the cable is inserted through the cut.