The monetary financing advocated by MMT is just smoke and mirrors

According to Olivier Blanchard and other economists, advanced economies can afford to take on much more debt

It is not enough for a government to ensure that it can afford to make its interest payments; it also must show that it and its successors can repay the principal. 

Raghuram G. Rajan Project Syndicate 30 November 2020

https://www.project-syndicate.org/commentary/borrowing-and-spending-limits-in-ultra-low-interest-rate-environment-by-raghuram-rajan-2020-11

Raghuram G. Rajan, former governor of the Reserve Bank of India, is Professor of Finance at the University of Chicago Booth School of Business and the author, most recently, of The Third Pillar: How Markets and the State Leave the Community Behind.