It's not about the format, it's about the access. I'd be fine with a CSV of my bank transactions, even the completely broken pseudo-CSV that my bank outputs. What I need is the ability to pull that CSV with an API call automatically, instead of having to log in to the bank (which takes almost a minute and involves retyping numbers from a mobile device), and navigate to the right place to find the CSV download (which takes another minute).
Basically, the bank UX sucks for my needs - and I'm guessing, for most people's needs[0]. Cynic in me says that the reason I can't get an API access is because somebody then would make an interface that doesn't suck, and the banks would lose the best place they can upsell people with financial products.
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[0] - There's a reason why "preview your balance and last transaction" feature shows up in mobile banking apps these days.
The other thing you need is a transaction I'd. Transaction amounts can change over time. I got caught by this when I tried to build my own tracking tools. Credit card transactions in foreign currencies commonly change over time. My balances never added up and I couldn't figure out why. Turns out most banks support ofx. That has IDs so you can track the changes.
Generally speaking, yes, presumably because API access to checking and savings accounts is only applicable to businesses 99% of the time.
Most consumers, even programmers, don’t have a real need for API access to their accounts that isn’t already covered by simple CSVs or Plaid.