Those apps can all be replaced by a website, and most banks already have those websites, which means if all the banking apps on earth stopped working right now the solution wouldn't involve anything more complicated than stabbing your finger at different icon on your phone and typing the name of your bank into a search engine.
not being funny - if the internet goes out how does a website make this better?
I think this comment is the tech equivalent of "if they can't eat bread, let them eat cake"
That’s beyond about 90% of the population.
There are very few things that would cause banking apps to stop working while their websites continue to function.