This is just one idea. It is not meant to solve every problem. Though, frankly, I don’t think your critique is very relevant. The poor typically have little or no savings and spend their money immediately. So they should be largely unaffected by this. And increased spending and lending by the more privileged should benefit the poor to some extent, as will the reduction in the wealthy’s spending power.
But yes I think further ideas and programs would be needed to fully solve poverty. This type of currency would easily accommodate a UBI or similar benefit programs since the natural reduction in money supply would solve any issues of inflation typically associated with large direct payments to citizens.
It’s such a broad body of work that it’s hard to list all of the issues I have it it. I guess the biggest issue is just that Marx’s writings were an early attempt at describing a more rigorous case for social reform before more scientific theories of social change and economics were developed. So while his ideas were groundbreaking and innovative at the time they were written, not all of them have held up or are relevant to today’s world. And yet I don’t see many Marxists who have been willing to seriously dissect his ideas and take the useful ideas while discarding the bad or irrelevant ones. And in fact, those few who are willing to take a more critical stance are often ostracized and deemed “revisionists” which strikes me as a frankly absurd accusation. If you are not revising your theories then they are no longer theories but mere dogma, and that seems to be the state of mainstream Marxism today.