I have read a number of articles recently on phones as the new electronic wallet, that will soon replace everything except maybe the large-screen TV (watching Avatar on a 3.6-inch screen is less than impressive). One title was "The End of Cash?", in which people said (on cue), "Oh, my life is on this little phone".
A few million phones are stolen in the U.S. yearly. A wise thief will attempt to snatch the phone either without your knowledge, or when you are far from help, so the race against time (the thief trying to crack your phone and get to your data before you call, on someone else's phone, to suspend service) is in his favor. And until you get a new phone and configure it, you're like an old-time traveler who has lost his Traveler's Checks and is 100 miles from the nearest embassy or AmEx office.
Meantime, paranoid that I am, I am quite happy with my flip phone from the days before smart phones. It makes phone calls, and it can do text. Period. If it gets stolen, the SIM card will contain nothing but a bunch of phone numbers. No apps that link to my banker and stock broker; no access to my retirement plan, or even my medical records. I don't mind the "delays" inherent in doing my banking and such in the same way I have since the 1960s. The only use I have for "online banking" is to make sure I have enough balance before writing a big check, like for a major auto repair. Some "conveniences" come with risks I am not willing to take.