The thing that would sell me is easy access to my data: I want to be able to get my complete transaction info via API for use in other apps. Manual export is necessary, but automatic access to authenticated apps would set you apart. Open banking for the win!
Yes, using an API will be more secure than giving my bank account number and debit card information. With the latter two you don’t know where that information is going, and who could intercept along the way. Companies are putting extra charges on credit and debit card use, and those transactions can take several days to settle. User grants permission for either one off, ongoing, or timed consent, for example, self-destructs every 30 days, user gets a warning to re-authorise to ensure only companies who need that consent is still accessing the API.