Firstly, any biometric technique can be beaten. Against a known, committed foe, it is almost impossible to defend with surety. And for that matter, who can't obtain the pin code of any other user given a short amount of time and focused attention? The notion that "if someone takes an IR high resolution, close photo of your iris they can defeat your security" is asinine given that the same people could obtain your pin in a million and one ways.
These mechanisms are to induce users to use some security, and the primary defense is against lost or stolen phones, making it convenient enough that it isn't disabled.
Secondly, how did this somehow turn into yet another Royal Apple spiel? Aside from the easy beatability of the Apple fingerprint sensor, why wouldn't you compare the fingerprint sensor on a Samsung?