This is the 'problem' I need solved as well. Sync across multiple Financial institutions is a nightmare. If the CSV import can be automated with some Plaid/simplefin bridge that's reliable, I think it would be a nobrainer for a large group of us to selfhost instead.
It's still limited to just one party, that's heavily regulated for compliance. Not perfect, but a step better than exposing to apps that can have bigger surface area of exposure.