a very low rez grid, this is what the iPad Pro has, I don’t think the iPad Pro is any better…
The FaceID front sensor has a lot more resolution but very small field of view and short range:
Making those inputs useful is not a side job, if doable at all.
Have you tried it Tom? I have tried both the iPad Pro and the iPhone 12 Pro, with several apps, they are equally limited and of questionable relevant use IMO. But I also use real scanners too so maybe my expectations are skewed by having professional standards.
I think you are right that this combined with Photogrammetry could be potentially useful. However it seems that there’s no money to be made in that space so no one in their right mind would put a team of expert scientists/developers to embark in such an alchemist project, for what? To sell a $9.99 app? this is maybe why the entire iPad ‘Pro apps’ ecosystem pretty much died, or is not financially viable. It’s a really tricky industry.
I’ve seen some neat results for interior room scanning where they take the input and make it into a cleaned-up straight walls room, which is much better than all the real estate ‘3D tours’ that show you how the house you are considering buying would look after a fire. But let’s just say I’d only trust that ‘cleaned up’ scan as much as I trust a drunk guy and a stoned one being sent to a job site to take measurements: I’d use that input to know if a couch would fit, not to build custom cabinetry without me doing proper measurements 
G