As a supplier of screws & fixings, Cabinz has been exploring this idea.
Their currency value aside . Low value coins have little intrinsic value, apart from their scrap metal value & a few uses , such as a screw driver.
In an inflationary environment, a metal coin can quickly become nearly worthless.
However, small metal nuts, bolts, screws, nails & other building materials fixings retain their value as a fixing for building things, even if the currency declines in value.
If a Government introduced such a "functional coin" . The may need to be stamped or engraved to stop criminals introducing their own screws to dilute the coin currency.
There are disadvantages , like difficult vending machine use, screws would have to be in containers to stop pocket wear etc.
Advantages are that the coins could be used as fixings in the house / garden , while actually being the households financial savings.
Alternatively the fixings could be used as local trading currencies , not national ones . eg Lets https://en.wikipedia.org/wiki/