Dr. Keen adds private debt to the problems that MMT addresses. He sees that private debt has caused 150 Recessions over the last 200 years and Gov. debt, specifically excessive deficit spending, has caused just 6 hyperinflations. [According to one set of definitions.]
He is calling for a Debt Jubilee to reduce the private debt loads. Functionally, he wants there to be a fairly large UBI for some years to provide dollars to those in debt to pay down their private debt. To be fair those who have little debt should get it too. Those who are filthy rich don't need it, so might not be given it, but they're so rich that they will not notice it. There may be some in the middle-class who don't deserve it, but I don't know who they might be. Therefore, it should be Universal.
. . . Steve wants people who have no debts be required to invest it in corps. so the corps. can pay down their debts too. I don't see why this is a good idea. The really poor need money now to spend now. Making them investment it just gives a way for someone to cheat them out of some of it when they sell those investments to get money to make their lives better now.
. . . As I see it the last few decades have seen flat or negative real wages that has led to the massive private debt. These flat wages have effected those who have no debts (because they had no credit because they were Black for example) just as much as those who do have debts to pay down (because they could get credit). Another reason for the high private debt level is the low interest rates that were kept low to try to get the economy moving faster, especially after the GFC/2008. This let corps. borrow too much.
. . . Basically, Dr. Keen's UBI is just to give the people money that they should have gotten over the last few decades to pay down their debts so that they don't have that debt burden going forward.
. . . I'm not sure about his amounts, but maybe in the US it would be $1500/mo. per adult and $500 to $1000 per child. This would be continued for about 3 years or so.
See also, the 1st reply for Dr. Steve Keen in his own words.
Mark Blyth & Stephanie Kelton talk about MMT in the current covid crisis .42 min. long
Another talk by Real Vision with Stephanie while on her book selling tour. 57 min. long.