When Open Banking first came out I could see the benefits but also the draw backs. For me, I think some of it is quite intrusive and allows organisations to analyse and make decisions based on a full picture of your finances. It certainly does more than inbound data only.
Now, you could argue this is a positive. It makes things far easier for banks to make accurate decisions rather than just a credit file. And easier for you to ‘prove’ your worth and satisfy regulatory requirements. But it goes deeper than that. Analysing all of this data for an automated decision may be similar to the credit file, but not in as much detail and it could also trigger some flags or ‘things the institution doesn’t like’ and automatically reject you.
For example, if you have a sick relative and financially supporting them. Or you take £500 cash out every month to give to the kids and grandkids, or are one of those kids granny gives you money for and deposit cash into an account? Or you like the occasional flutter on the GGs. Perhaps you like to visit gentleman’s clubs? Or maybe you donate to certain political parties. Maybe you send/receive money via crypto wallets.
If they don’t like your profile, would they take you on? Or, if you’re higher risk, would this affect any rates given? As we know, if a financial institution doesn’t like you, your profile or doesn’t want you any longer, it can sever all ties very easily.
Call me cynical (I know I am 
) but I personally think there’s an incentive for financial institutions to have access to your entire world, and knowing all about your habits and your personal life that, frankly, is (largely) none of their business for things siting outside of regulatory concern.
Open Banking is free. And it’s convenient. Which means you’re the product, not Open Banking…