I didn't know about them but I would say that they are mainly thought to be used as surface clamps to hold relief carvings (as suggested in their pics) to me the bench dog stop function for planning is more a "side use" than what I think they were originally thought for.
When I make relief carvings I fix them using wedges against a wood frame, that forces me to put some spacers between the wedges and the piece, with those I could just use a 1" plywood board filled with and array of holes and place them ad the edge of the piece to be fixed, their low profile would not interfere with my hands or tools and the cam function would make changing the position of the piece very quick.
Best regards,
Toni
__________________________________________________ __________________________________________________ _________________
I also dream of a shop with north light where my hands can be busy, my soul rest and my mind wander...