Fingerprint readers were always a joke and unreliable. Like on old IBM Thinkpads. Nobody used them, people "hacked"/fooled them easily. I was surprised that Apple brought them back, probably just for convienience reasons.
Just like the pattern lock (or face unlock and its variations) on Android phones, the idea is to encourage users to have at least some protection.
As an Android phone user, I hope to see this being adopted by the Android manufacturers (and I hope the Apple camp would shut up about people copying their idea).