At some point in the next five-ten years we will see this "feature" abused. Maybe Mozilla will use it to "soften" commonly used ad blockers to enable "acceptable" ads for Firefox users. Maybe Mozilla will be hacked by some government that wants to enable MITM attacks against its citizens, and Normandy will make that happen. Or maybe Mozilla will just cooperate with the government trying to do so.
You say it is "typically" used for benevolent purposes, but why should we trust Mozilla? Mozilla does not have a stellar history with this sort of thing and in my experience they do not take security as seriously as they should if we are to trust them with such a feature.
You say it is "typically" used for benevolent purposes, but why should we trust Mozilla? Mozilla does not have a stellar history with this sort of thing and in my experience they do not take security as seriously as they should if we are to trust them with such a feature.