What was Apple’s view points on introducing auto layout?

This constraint-based approach to design allows you to build user interfaces that dynamically respond to both internal and external changes.

External changes occur when the size or shape of your superview changes. With each change, you must update the layout of your view hierarchy to best use the available space. Here are some common sources of external change:

    

    The user resizes the window (OS X).

    The user enters or leaves Split View on an iPad (iOS).

    The device rotates (iOS).

    The active call and audio recording bars appear or disappear (iOS).

    You want to support different size classes.

    You want to support different screen sizes.

Auto Layout is also a key component for supporting Slide Over and Split Views on the iPad.

Here are some common sources of internal change:

    

    The content displayed by the app changes.

    The app supports internationalization.

    The app supports Dynamic Type (iOS).

Finally, if your iOS app supports dynamic type, the user can change the font size used in your app. This can change both the height and the width of any textual elements in your user interface. If the user changes the font size while your app is running, both the fonts and the layout must adapt.

references:

https://developer.apple.com/library/prerelease/ios/documentation/UserExperience/Conceptual/AutolayoutPG/index.html#//apple_ref/doc/uid/TP40010853-CH7-SW1