When Apple announced the iPhone X last week, the most sophisticated (and widely predicted) feature revealed was the facial recognition approach, called Face ID. But by choosing to go all or nothing with the iPhone X — it's only Face ID, with no support for Touch ID — the big risk for Apple was that all the companies that support Touch ID in their apps wouldn't quickly make the move to Face ID. So Apple made the decision for them.
As the recent healthcare debate in the U.S. demonstrated, it's extremely hard to take back something people have grown to like. Apple's choice of biometric authentication faced the same problem. If Amazon, Chase, Fidelity or any of the other major companies whose apps use Touch ID as a way to log in without a password had failed to make the move to Face ID, their customers would have been forced to go back to typing in long passwords. Apple, ever mindful of customer experience, chose to not permit that to happen. To make sure that companies use Face ID in their apps, Apple simply didn't give them any practical choice.