I haven’t used this technique in a while. Probably it’s an exercise I ought to do once in a while just so it stays fresh in my mind as an option. Mostly, I’ve used it when prototyping, making one-off items. I remember when I was introduced to using a cold chisel this way many years ago and being surprised how accurate and effective it was.
I found a couple of clip art images showing the technique. Both images show a straight line cut. The last time I remember using it was for cutting some blanks for making magnolia leaves. Those leaves have a gently curved edge and the technique still works quite well as long as the waste material is removed or bent out of the way so it doesn’t obstruct the positioning of the work piece. The result is a curved appearing edge line which was cut with a series of short straight cuts. That’s actually how the SketchUp drawing program makes curved lines too.
For me, this method would become impractical for sheet thicker than about 12 gauge mild steel or 8 gauge copper or brass. Also, if the project is going to require a lot of pieces I’d be looking for another method.