It seems like it may be a gimmick, I will continue to use a compass for scribing. I typically have to scribe next to uneven surfaces that to get them tight I need more detail than that tool would give me.
I might give it a try. I have a terrible time with fumbling stuff when I scribe. Never can see to hang on to things. This might help since the pencil and the tool are solid to each other and it looks like something I might not drop.