They need to keep it in the range that doesn't fully destroy people but also doesn't let them escape. If you run a usury business, you want your clients to be

They need to keep it in the range that doesn't fully destroy people but also doesn't let them escape. If you run a usury business, you want your clients to be spending a good chunk of the money on stuff like alcohol and cigarettes, so they keep coming back and it remains stable. Once your clients escape their trap, they may qualify for better credit options.