Agree with the weakness, but the benefit of provenance is still there. You can't tell if the picture that person took is of an AI image, but there's some value in saying "I took this" and being able to prove it.
1) I see a photo online and doubt it's provenance
2) I contact the photographer and ask to see their cloud image (???!)
2a) I borrow someone's mac to download the image (.jpg?) and it can be verified on that?