What problem does this attempt to solve? Their slack example doesn't seem particularly pressing.
Bank have been very very reluctant to open their systems via API access, which is why there are services like Yodlee. Basic charge is around $20k per annum plus pay per use. They are making a LOT of money, but the service is imperfect because they work by screen scraping the data from bank accounts. They have some direct integrations with banks, but my understanding is that the vast majority is still done via scraping. From end user perspective its terrible - you have to give them your login credentials, and supply OTP/2FA (if your bank uses this) every time you want to pull data in.
The banking industry is being dragged kicking and screaming to modernise and offer proper API access like this.