It sound more like Cambridge Analytica will be able to get access to people's banking data by making themselves an AISP, while I still have to scrap my fucking bank site to automate my own finanses. This is totally backwards, but that's profit motive for you.

Cambridge Analytica didn't make or market such an app to them. It was some academic who made the app and then turned around and sold the data. This academic has now been largely erased from the story, presumably because journalists tend to like academics and anyway "one guy screwed up" is not a story whereas "clash of the corporate titans" is.