Chisel-point pencils, along with their mechanical cousins (flat-lead pencils), are very interesting to me. The shape and structure of the leads allow you to maintain a more consistent line width when drawing long lines, and are less likely to break as circular leads with conical points might. These examples are from an Eberhard Faber Van Dyke samples folder: along with the full range of rounded-lead pencils there are also six chisel-point pencils, in 4B, 2B, HB, 2H, 4H, and 6H.
But flat leads are not just for draughting and lofting, they could be used for lettering or other applications where varying line widths are needed. Something that comes to mind though is the sharpening of chisel-point pencils. Using a rotary sharpener might be a good place to start, then you could snap off the tip or perhaps whittle your way down to a flat edge. The pencils in this kit look like they were sharpened on a sanding belt, but only on four sides. And, each side is aligned with the lead.
And another angle:
Chisel-point pencils still exist today in the form of carpenter pencils, though the leads are considerably thicker. I believe there is a vendor or two out there who offers flat-lead mechanical pencils of sorts, too.
I’d still like to see these come back in some way.