Interest-free credit is a total nonsense.Nobody would give a loan without any interest.
This guy doesn`t know anything about economics and finance.
Is this Usury thing some other altcoin?
Well to be fair, I think some people would lend money interest free. For example, I bought a car from my parents and instead of paying them they allowed me to make monthly payments with zero interest. Of course, they trust me and that's sort of the core of the issue I think, as @dinofelis said.