The Butterfly handle encourages a comfortable hand position when cutting a "Bob", or other techniques where the wrist would normally be bent when using other handle designs.

By placing the index finger on top of the scissor in front of the screw, you will achieve superior control in your technique. 

 

Also this helps to place your other index finger under the scissor for control.  Please note the position of the thumb and be aware to use the correct hand positions.

 

The thumb is moving in a natural and a relaxed way.

The Butterfly handle rings are sculpted for the finger to be positioned so this cutting method will be very comfortable and ergonomic.