The point of contention for me is the focus around stressing the platform's encouragement of responsible spending and it's strength as a budgeting tool for consumers. The offering from a retailer perspective though is that it stimulates incremental demand and thus giving away a merchant fee of a low single digit percentage of the transaction is offset by the incremental lift in revenue that would otherwise not exist. 

From the FY18 Results presentation;

"Without Afterpay, many (39%) customers say they would look elsewhere or not purchase at all (23%)."

The risk is that the benefits of the cashflow management functionality is driving an overestimation by the customer of their real purchasing capacity. I understand there's no interest charged (and thus more disposable income to spend), but credit cards can also offer >1 month interest free periods on purchases, which is arguably an equivalent service if the customer is disciplined enough to pay back in instalments within the interest free timeframe.

"Mr Brody said it appeared that more customers were contacting the National Debt Helpline about Afterpay."

"Customers of buy now, pay later services such as Afterpay were also starting to raise some concerns to financial counsellors about this type of credit, Ms Guthrie said."