Comment by CMay

Maybe what they see is that most people who turn it off will leave it off, but some people turn it off and turn it back on as a part of a pattern/habit around temporarily putting files on OneDrive they don't want to scan.

For example, people who don't use their encrypted vault on OneDrive, so they upload photos that should otherwise be encrypted to their normal OneDrive which gets scanned and tagged. It could be a photo of their driver's license, social security card, or something illicit.

So these users toggle the tagging feature on and off during this time.

Maybe the idea is to push these people's use case to the vault where it probably belongs?