Banks are world class leaders in technical inertia. Almost certainly at some point when they’re designing their system they’ve got a interface from the 1970s or maybe even the 1980s if it’s a new bank, that has to work with everything else which has the limited input fields. And that just propagates to all the other systems in these weird ways

Oh yeah we’re using a file system that integrates over LDAT but it only looks at the first eight characters cuz the rest are used for the domain etc etc etc