Really? It's called an application. You write one specifically for the bank. Also the cost of the electronic transfer doesn't have anything to do with the problem.
That doesn't work, either. The only way to commercially viable would be for a third party to sell such a package (and I used to be in that business). However, if such a thing becomes prevalent enough, it will get hacked as well. Plus, it has to go over the internet anyway unless you expect bank customers to use speical hardware.
It's amazing how simple things are when looked at by uninformed people.
I assure you, it is not as simple as you seem to imply.