Regardless of the fact that most of the banking sector is still stuck on IBM mainframes from the 60s-80s running COBOL:
I have seen accountants who's only job it was to come in every day and do the same sums on Excel.
I've seen people insisting on a calculator and a printout so that they could sum up columns of an Excel table and send the results back via email.
There are valid reasons to move slowly. Transition costs to new systems are usually immense and the process is a nightmare for banks, but none of what I described fell into that category. It was just people refusing to change their ways. A report for treasury could've been instantaneous with a super simple live updating dashboard. But no. Instead, the CEO got an Excel file emailed to them every week that was put together by 40 people – many of whom entered the numbers manually.
In the industry we have come to call people involved in these tedious processes "hamsters", because they might as well be going up and down the escalator all day.
I don't think many people understand how excruciatingly slow banks move and how inefficient they are.
/cathartic rant over
Edit: (I should add for context that this was a fairly large bank in continental Europe)