Does that sound like something that would be feasible to produce/practical in the real world?
Desirable? Well, you've created a system that authenticates a camera as being at a place at a time. It's a good way to authenticate photos, but a bad way to stay anonymous.
How do you feel about photographers and journalists becoming even larger targets for anyone who wants to keep a secret?
The issue is : does it authenticate that a particular camera that belongs to a particular person is/was at a place at a time and produced an image - because if so then if the device is found in a search the owner/user/keeper is in hot water.
So the camera must be anonymous - but it must be impossible for a lie about the place and time to be encoded into the image.
It's perhaps worth considering that an authoritarian government might not trouble itself with such legal niceties. All they have to do is mandate that journalists with cameras register their keys, make possession of a camera with an unregistered key criminal, and track sales / border entries. China springs to mind as a country that might do such a thing.
Again, you're absolutely correct in asserting that anonymity of camera-user is important! It's just perhaps worth considering how linking hardware to images might undermine that in dangerous ways.
Meanwhile secure enclaves are now possibly a lot safer, but as Kalium mentioned it might not be very attractive for everyone.
For forensics experts however it could become very useful I believe.