If someone is going to remove your finger to access the phone, you probably would just give them the four digit pin. This is a way to get normal people to use

If someone is going to remove your finger to access the phone, you probably would just give them the four digit pin. This is a way to get normal people to use better security than nothing and to give them the convenience of not having to enter an App Store password every time they install an app. It's not meant to protect special forces operatives in the field or CIA analysts' contact lists.