Gold a valuable commodity and a beautiful one. It, by itself, will never be money again.
How would small currency be made? A dollar is about 1/1500s of an ounce. You would need a microscope to see a dollar much less a dime or penny.
Countries claiming to be on the Gold Standard with convertibility were on and off, off and on depending the needs of the nation at the time. See the history of Great Britain during the Napoleonic Wars.
Countries on the GS are handcuffed by it (see its role in the Great Depression). It would be highly impractical to impose one due to the lack of gold in the world and other reasons.
Silver would be under the same negative though less initially acute. How much silver is in a dime?