The current depth sensor in the X is unusable beyond face recognition. If Apple is serious about AR, the longer range rear sensor will enable users to 3D scan objects, rooms and homes. Solutions like
http://geocv.com that combine smartphones with sensors, will be reduced to just the phone. Everybody will be able to create virtual tours like
http://matterport.com. The winners will be the software platforms that depend today on expensive scanners to offer immersive experiences.
Also, imagine if you are allowed to upload a virtual tour of your business to Apple Maps. Like Google does for Street View, they might be able to crowd-source 3D content (although that's not in Apple's DNA ).
Today, to capture reality, you need a 3D scanner or photogrammetry. Tomorrow you'll need a powerful and expensive iPhone. Not everybody will use 3D, but when times will be right for the AR glasses, there is going to be demand for lots of 3D objects.