Screwdrivers are hard on scissor screw heads. They can slip and damage the screw head or injure the operator.  Shear screws are designed to loosen hard. These Set-Screw Pliers are designed to turn the screw without slipping or damaging the slotted screw head.  A squeeze of your hand holds the bit squarely in the head and the handle provides the leverage to turn the tightest screw.