People often ask me about that little electric engraving tool shown in this picture. Some want to find a tool that will make engraving easier and a few have asked me if the tool would be kinder to arthritic hands. It's made by Foredom and it's called a micro motor. It spins at extremely high speeds and works the same way a dentist's drill works (it sounds like one too). There are other tools that work, but this one is the best I've found. There is no flex-shaft to struggle with. The hand piece is smaller than other brands, so engraving with it is like drawing with a fat pen or pencil. It's very handy when removing large areas of material. It's expensive and, like any other power tool, it can be dangerous. If the operator is distracted or relaxes, the bit (I use an inverted-cone shape) can bite into the material and pull the tool with it, out of control.
I use the power tool for most of my engraving. When I want total control and I'm working in a small delicate area, I use hand tools. For the most part, I can't finish engraving a block any faster with the power tool than with hand tools and I can't say that the power tool is any easier on my hands, arms or back than using the hand tools.

I have no answer for the question: "Then why use it?".