As the tool is relatively lightweight, it can fit into a pocket or hang from your belt, making it easy to carry around with you. You can even take the tool up on to the roof with you and cut the slate as you go.
Spring-loaded handles
Slate and punch cutters have spring-loaded handles, which means that you don’t need to pull back the handles after every cut, so the process is continuous. Another advantages is that you don’t need any special training to use this tool.