We’ve all stood at a self-checkout machine, frustrated as it freezes or flashes errors. Though promoted as “convenient,” these kiosks were really designed to cut labor costs—not help shoppers. Sylvain Charlebois of Dalhousie University’s Agri-Food Analytics Lab says retailers like Walmart and Target invested heavily in self-checkout to save up to 66% on wages. But instead of smoother shopping, customers...