I know that Starling is focussed on making the best current account. But I can’t see how this particular product can be provided by the marketplace.
They way I manage my finances is to spend everything on the credit card (extra security and delays payment) and then repay the full balance each month. I believe many people budget this way.
So a Starling Credit Card with all the fantastic instant notifications and categorisation makes a lot of sense to me. I can’t imagine it would be too complicated to integrate and would widen the customer base for Starling.