I just need to supply my bank statements to the accountant annualy (bank is TSB). They have a set of rules (less that 150 lines, not more than 3 months) that constrain how you can get the statements, and a 5-step process to open up the UI to download one, then select the dates, etc. You may imagine it's simply error-prone and repetitive.

A few years I didn't even need to change the script. But even when I needed it wasn't something too complex. As long as you constrain the expected behaviour and error early - it works perfectly well.

> Over 18,000 banks provide APIs

Please consider adding a source for this when you have a moment.

And how much time would that take me to register my own application to download a few statements instead of using the browser?

My bank is TSB, but at that time there was definitely not even a program to register a developer account with them.