Metal coins are generally end up worth more than their face value. This includes not only gold and silver, but copper, zink and nickel as well.

This happens because when any government issues a coin, say a penny in US, they only hope to steal say 5/10 of your money. They don't believe their citizens are so dumb, as to not notice. So, they set the "realistic targets".

As they proceed stealing, it becomes clear, that their citizens are way dumber that it was originally estimated. So, the government pushes on, say, eventually stealing 9/10 of the wealth of the people, by the time they retire that coin, and issue a new one.

Now, as their stealing progress crosses the 5/10th mark and touches 6/10, the metal in the coin consequentially becomes more worthy than the coin face value. At this point, a government institutes a law prohibiting export of coin and smelting of it (because supposedly that smelting hurts the bottom line), and proceeds on it's way to 9/10th.

Nope they won't

Efficiency and all you know? haha

So, if you don't believe in credit/debit cards and if you want government transactions to be conducted in a cost efficient way why are you using dollar bills?

A dollar coin is much more efficient and hard to...

Umm well...coins of all values are smart to use...for a variety of reasons.