Threaded fasteners do a more reliable job when accompanied by washers. Most notably, washers protect the surface from damage during installation. They distribute the pressure and prevent the fastener from moving or corroding. Skipping on washers can dramatically reduce the lifespan of how your product is put together.
Wing screws are a type of fastener designed to be tightened and loosened by hand. Also known as wing thumb screws, they feature wing-like projections that form the head of the screw and provide thumb and forefinger leverage for turning.