Urban 'flint knapping' arrow heads.

[Timelord]

"Knapping" silica based materials produces more than just arrow heads. Other than modern rare ceramic knives, then silica materials like flint & glass are the sharpest possible. For 98% of our history, ancient humans were able to very efficiently and cleanly butcher small to giant game with these implements. They are not useless, just relatively labour intensive & inconvienient to produce & use and in our modern age. The time it takes to strike a simple sharp flake for a knife or scraper is minimal to that which it would take to reshape a metal object with hand tools.
It is a useful skill if you find yourself outdoors with no available modern materials immediately to hand. In areas of the country with flint or chert or even quartz and all areas that glass can be found, then prospective blades/tools are can be seen to be littered across the landscape in the eye of the knowledgable beholder. A struck flint/glass flake will be sharper than 99.99% of any steel bladed implements out there.
I personally will not waste time making difficult to knap arrowheads as they do not feature in my plans, but the ability to be able to strike off in one blow an exceedingly sharp flake to use as a knife or scraper is a very useful skill to have in reserve. It is worth looking at the microlith flint toolkits in their little tool rolls that the Neolithic peoples used to carry around. An efficient lightweight & v.small toolkit for most scenarios in their environment. TL.