The way everyone's talking, you'd think Apple was taking away the four-digit PIN! But they're not... The fingerprint ID is just another option , which you don't have to use . So titles like this are just incorrect. Fingerprint ID isn't taking away any of your rights, because you can still use the PIN just like you always have . I mean seriously, what the heck is going on here? Why on earth are people getting worked u…
Touch ID requires both a fingerprint and a PIN. If the phone hasn't been unlocked in 48 hours or has been rebooted, you have to enter the PIN. This would probably protect your 5th amendment rights in the case of going to court (since it would probably take >48 hours).
Touch ID is there to make PINs more widely adopted, by minimizing the inconvenience of entering a PIN every single time. That's a great boost for security.
Source: http://blogs.wsj.com/digits/2013/09/11/apple-new-iphone-not-...