There are two people A and B. They pay each other $100 every month with net $0 profit. Then A decides, hey I want to do this project that needs $200 to complete, so I will stop buying from B for a month. A now has $200 on his account and B didn't work for a month because there were no customers. A wants to spend $200 on the project and pays B but B can only do a months worth of work. At this point the only way the $200 can represent a claim to 1 month of labor is if productivity doubled or the population grew and we now have person C ready to work on the project.

It's pretty obvious what the problem is. If the value of the money is kept stable while the real world deteriorated (through unemployment) then A becomes a leech on productivity or productivity growth. I.e. the way he is maintaining his savings is by exploiting the slack in the labor force. Thus anyone who wants to save in USD is dependent on an underclass that willingly sacrifices their labor. I don't see how this benefits poor people. I can kind of see how this benefits a middle class founded on exploitation. I definitively don't see how reducing the savings until they reach their real value benefits an upper class. They are the ones that want their money to be stable because it means they can extend debts arbitrarily long into the future at their own whim.