Why mint half dimes and 5 cent nickels at the same time?

Monstavet

Just curious on the history of minting both denominations at the same time - well, they are the same denomination - but why have the overlapping years of production (1866-1873)? Don't tell me the vending machine lobby had a lot of sway back in the 1860s!

Seems a little useless, kind of like...oh I don't know....circulating dollar coins and paper dollars? That is working REALLY well.

CaptHenway

Silver coins all disappeared from circulation during the Civil War, including half dimes. The denomination was very useful in day-to-day transactions, so they authorized a copper-nickel temporary replacement. In the meantime they kept making Proof half dimes for collectors, plus a relatively small number of business strikes just because.
The larger, earier-to-handle "nickel" proved to be popular, so before the large-scale production of fractional silver resumed the half dime was eliminated.