I learned about hook tools when I started building and using a pole or foot powered lathe. But in my 20+ years in working with electric powered lathes I have not heard any "expert" recommend using a hook tool with an electric powered lathe, but as you can see some people have figured out how to do it with outstanding results. His style of introducing the edge of the hook to the wood is probably akin to rubbing the bevel of straight edged tools as you feed the edge into the cut. I'm not positive but I suspect that there is a bevel on the outside of the hook tool.