There was also a very brief mention of a "depth api" before they started talking about the actual ARKit. is that endpoint documented anywhere?
https://developer.apple.com/documentation/avfoundation/avdep...
> Camera: Updated video and image compression, improved Portrait Mode with support for low light, plus a new Depth API for developers.
from https://venturebeat.com/2017/06/05/apple-announces-ios-11/
So you can now access a stream of depth data. I'd put money on ARToolkit using this stream when it's available. For now, it would only be from the iPhone 7+.
[1] https://developer.apple.com/documentation/avfoundation/avdep...
Perhaps that data isn't granular enough (or fast enough) to be useful when doing AR compared to the normal camera picture plus the motion sensor data.