first result, specific to banking, i got from a forensic expert:

Randal Wolverton, a certified public accountant who serves on the American Institute of CPAs’ Forensic and Litigation Services fraud task force: “My preference is to bank with computers in a secure environment, as thieves may find smartphones more attractive to attack,” he says.

Since smartphones travel with you, they give fraudsters unique opportunities. If a customer is standing in line at a grocery store and decides to check her bank balance on her phone, someone could be looking over her shoulder and guess the password. That kind of situation is unlikely to arise when banking on a computer at home, Wolverton says.

this is pretty in alignment with our forensic research for network hardening when it comes to kid data, too. a phone is just a snitch that lives in your pocket. the less you do from it, the more secure you'll be. you should really only be doing critical things, like banking and logging into your labor or educational institution, from trusted hardware on a trusted network. phones are fine for looking up business hours, interesting tidbits, and the like, but you shouldn't do anything you specific that matters to your life if you can help it.