Frank,
If I recall correctly, it's one of those 'good ideas that didn't work' Wonder tools that was briefly marketed maybe twenty years ago.
It was intended for use in a circular saw, for cutting curves.
A neighbor back then had one - or at least one similar to it - and was going to make a curved front bar for his patio. As I recall, the kerf was about 3/8" wide, and VERY rough. Also, about halfway through, Lou lost control to the saw and it went skittering across the veneer face of the plywood he was cutting. I never saw that blade again...