You should check out the research that was done on this. The technology works - we're simply the first to really productize it in this manner.
This isn't entirely clear to me. Are you saying something to the effect of, "While historical images would indeed be compromised, there is value in at least the current images not being compromised"?
I see what you’re asking and I share those concerns. This approach seems like it would only stop casual attempts, not determined large scale automated bulk collection, yet it is pitched as if it’s effective or could be improved to be effective. I would expect that its usage would be able to be detected in a photo even if it works, which would itself be meaningful information which could be tracked, like DNT in web browsers.