This is apparently a Thing now on various woodworking pages. IIRC Rob Cosman has
been demonstrating this technique for some time and may even have developed a
handled tool version.

Cheers,
John Johnston

“There is a fine line between hobby and mental illness.”

Ed wrote in part:
When you cut the tails of a blind dovetail joint, your saw is at an angle and
there is extra chiseling to do to get into the lower corners.  You can use a
scarper blade in the saw kerf as a very narrow chisel by tapping it down and
completing the cut.  I’ll have to give it a try.  Just thinking - a piece of old
saw blade would work too - just polish the arrises (arrisi?).  You could even
put a hardwood striking pad on it.