I think this is very handy, and I know my colleagues (who don't know how to use AE) would love something like this to update animations. The question is, how are these photoshop files created?
Initially, I thought it was as simple as copy and pasting keyframes from After Effects into Photoshop's timeline, though that doesn't seem to work. Then I thought maybe the author the example above eye-matched and created keyframe in Photoshop, but I've seen some more complex examples since.
I agree with what you are saying. Though I am asking how other people have managed to get Photoshop to do this already.
The screenshot shows a Photoshop smart object that has transform keyframes that track it to a 3D rendering of a phone. I am not sure if these keyframes were eye-matched created, or if they were generated somewhere else?