Usury, which is to say lending at interest, will inevitably in aggregate lead to a tiny minority owning virtually everything. This is obvious to anyone who has basic high school math and understands that interest compounds geometrically and wages grow linearly at best.
How do you run the economy without interest?
You can already see some fintech startups attempting equity-based home "loans", in which the "lender"'s lien is on a percentage of the future sale value of the home, not a fixed dollar amount. It will be interesting to see how this develops.
I'm not sure how financing on consumer debt like credit cards and non-commercial vehicles would work, though. Perhaps discouraging consumer profligacy would be a feature, however, not necessarily a bug.