how to make money by the loss of value in a currency:
Instead of issuing gold certificates, a government converts gold into currency at the market rate by printing paper notes. A person redeems an ounce of gold for its value in currency, keeps that currency for a year, then trades the currency back in for an amount of gold at market value, which may yield a different amount of gold from that started with if its price has increased or decreased during that year.
So basically the less your money is worth, the more the bank likes it, it's profitable.
The fact that the US dollar is used for foreign trade in massive excess of the value of the US economy, when the dollar loses value, the people using the dollar who gave over their stuff, and now have a pile of dollars of diminishing worth... they're paying.
So I get you to sell me a rolls royce for £10,000. I have a rolls royce, you have a stack of paper notes... and next week the £ is now like the lire, you'd be pissed, that'll just about buy you some shoes.
Welcome to the weimar republic.