Will they be reporting the payment History to CRAs ? If so how are they going it the Credit report with Credit Bureaus ?
Sounds sketchy to me. I wouldn't be comfortable with some new company having continuous login credentials to my bank account. No thanks.
They use a 3rd party for accessing your accounts (Plaid - it's one of the popular ones among fintechs). Companies that use Plaid don't ever get your credentials or data directly. It all comes via Plaid.
I work for a fintech myself (small business loans), so the tech didn't concern me and i gave this a try. The preapproval is bogus - all it really asked was your monthly income and bank account balances. Then it tells you are approved "up to $___", but that there's a 4-8 week wait "to manually process your application". It sounds to me like they are still not actually live, but nothing on their website seemed to indicate this is actually still just a waiting list - which rubbed me the wrong way.