I don't think it's really the utility of deniability, rather a slippery slope of and loss of freedom from a mechanism that stamps every photo taken and silently

I don't think it's really the utility of deniability, rather a slippery slope of and loss of freedom from a mechanism that stamps every photo taken and silently cryptographically ties it to the photo taker. That could obviously be used for good or bad purposes. Reminds me of tracking dots in printers. It was implemented to provide a way to track a document to its source.