But why would you have concerns downloading a banking app directly from your bank? You have trusted them with your money, after all... With apple, you can't install and run software even from sources you trust, outside of apple.
Apple policy could be described as an insult to the scientific principles that led to computing, let alone user rights to run software on devices they own (somewhat established in courts).
"In the famous Apple v. Samsung lawsuit, Apple even claimed ownership of geometric shapes such as rectangles with rounded corners", cited from
The crisis of intellectual monopoly capitalism, Ugo Pagano