It becomes a bad thing when this additional credit goes, not to entrepreneurs, but to Ponzi merchants in the finance sector, who use it not to innovate or add to productive capacity, but to gamble on asset prices. This adds to debt levels without adding to the economy’s capacity to service them, leading to a blowout in the ratio of private debt to GDP. Ultimately, this process leads to a crisis like the one we are now in, where so much debt has been taken on that the growth of debt comes to an end. The economy then enters not a recession, but a Depression.
This is exactly what has happened, and the result will be just what the author says it will be: a depression.