A credentialed economist should put a stake through the heart of the heart of MMT. Two simple critiques: 1) Relative to a financial statement (i.e. budget), it is difficult to predict and measure inflation. This difficulty lowers the likelihood of government fiscal responsibility and increases the likelihood of devestating inflation. 2) A basic second-order effect: What happens when people realize transfer medium is…
Arguably, to some proponents of MMT/in some versions of MMT, this is a feature and not a bug. Economically speaking, stored value at rest isn't "interesting", it's a potential indicator of waste or inefficiency of resource utilization in current flows. I've heard the argument that the real "bug" here is the human psychological need to "hoard" stationary value/"keep score", which admittedly is a very hard problem to solve, but having hard problems to solve isn't necessarily a disproof of a hypothesis such as MMT.