If you want to see how much a deflationary currency fails as a currency, just look at bitcoin. The wild value swings are caused by more people hoarding it than using it as a currency, which is caused by it being deflationary. Now look at monero, which is inflationary, is largely used for day to day purchases (of mostly illegal items) and has a much more stable value, which is one of the key attributes of a good currency.
The USD was metal based, in one way or another, from 1792-1971, with two brief interludes after the Civil War and Great Depression. That's a really good pedigree.
So our current inflationary system only really kicked off in 1971 and is already looking somewhat clearly unsustainable. But what makes this particularly relevant is that 1971 was also right when major breakthroughs in computing were about to unlock a huge economic leap. That helped briefly enable the infinite exponential growth that this inflationary system requires. Without that, I doubt this system would have seen its 50th birthday.
On the topic of stability, the Fed worked to calculate inflation levels from 1800 onward here. [1] You'll notice that from 1800 to 1950 prices never shifted by more than 50% relative to the initial baseline of 51. That's pretty wild if you think about it because it includes the Civil War, both world wars, Great Depression, Spanish Flu, and all of these sort of things. Then in just the relatively calm ~50 years from 1971 to to today, prices increased around 800%.
for much of that time you could not actually receive any metal from the US, notably after the great depression domestically. The entire issue is that the US economy grew far faster than the supply of gold so could not physically purchase the required amount of gold as it did not exist.
