So if some of the worlds most elite biometric hacking experts need 48 hours, knowledge of the registered finger AND an almost perfect print left on the phone, I think it actually proves how secure the system actually is. If this was that easy they would have cracked it Friday, but it clearly took them several attempts despite being (some of, if not) the best in the world at forging fingerprints.
Yes you can't change your fingerprint, but you can change which is registered on the device (or with the bank, or whatever) and I'm guessing financial transactions outside of iTunes might require a passcode also. It's just another layer of optional security. Clearly it shouldn't be relied on as a foolproof, 100% secure authentication system but it certainly shrinks to pool of people who can gain access to my phone from "anyone who sees me unlock it several times a day" to "fingerprint forgery experts and highly sophisticated and motivated criminals."