Taking a walk to the park without the iPhone takes longer, because you are forced to spend attention on everything but the phone. Distance = speed x time. If perceived time goes up; distances are greater. Ergo - world around you expands.

You can have a smart phone and not use it all the time. It's a matter of self control.

I assume he or she means that the world seems bigger as they're viewing it / paying attention more than if they were looking at their smart phone.