There are plenty of valid criticisms to be made of developed-economy monetary and banking systems. Finance capital seems to exert too much influence on our economies. Banks seem to make excessive profits. Excessive debt oppresses, and drives individuals, firms, and economies into a frantic search for income growth. The growth obession drives us into dysfunctional actions and outcomes.
Variations of “Social Credit” monetary theory (these days often described simply as ‘critiques of fractional-reserve banking’) often include reference to many of these criticisms, and appear to offer theoretical solutions. I assume that is partly why they are so popular among green movement supporters.