Looks nice. However the issue with all 3d streaming I've ever tried is latency. It's great if you're near the server. Terrible if you're far away.
It's hard so say what the input latency is for the head demo you shared. I guess about 100ms, which is totally fine for a mostly static scene with simple orbit controls.
However I also tried out the Lebron James vs Father Time game. Input latency is over 1 second so it's not playable. Any time I touch the screen it freezes for a second then jumps to the new location.
While of course I want latency to be as low as possible, the difference between 100ms and 500ms of latency doesn't register in the engagement metrics for these experiences. For millions of laypeople, it doesn't seem to matter that much. However, going from 670ms of time to first image (this service) and 2.5s (worst case) increases bounce rates by as much as 5 percentage points. PureWeb, which typically takes 35s to load, isn't suitable for any mass audience at all.
So imagine downloading a USDZ file for some AR thing. It's real, it's something people try to do. But the bounce rates on those experiences are insane, I don't know why Niantic funds them, there isn't anything you can do about it. There isn't a future for "it takes a while to load" on phones. That's the real constraint.
It's hard so say what the input latency is for the head demo you shared. I guess about 100ms, which is totally fine for a mostly static scene with simple orbit controls.
However I also tried out the Lebron James vs Father Time game. Input latency is over 1 second so it's not playable. Any time I touch the screen it freezes for a second then jumps to the new location.