I have used cheap air chisels a few times, and they have gotten me out of
jams. Once I had to remove the bed wood from a truck. In those days they
drilled down through the wood & bed and ran a nut up onto the screw. The
nuts were all rusted on forever tight, so I used an air chisel. Worked
great. I recently used it to cut through spot welds, worked great there
too.

Biggest thing is to make sure you are wearing leather gloves. I got some
nasty cuts and pinches learning that.

I don't know if there is a definitive use for those chisels. That's a tool
you tend to pull out when there isn't any other way, and one of the chisels
looks like it will work.

The chisels aren't all that hard, or mine weren't. I dressed new edges on them
every so often when I was doing that truck bed job.

GWE