That might have been their story, but Klarna is struggling to maintain their runway at the moment and that may have been the bigger driver
Their business model is an online payment provider (like e.g. PayPal/apple pay) that splits the payment into 3, 6 or 12 monthly payments, usually at 0% interest
The idea being that for the business the loss in revenue from an interest free loan is worth it if it causes an increase in sales