Oh my. I see the topic now. Thanks for pointing out.
I think all boils down to “Reply only to staff” or “private reply”. I remember seeing this request here in forums several times.
Just like there is “Whisper”, topics should have something to allow the poster to reply to a topic but make that reply not visible to anyone, but “private” - visible only to him and staff.
It’s a very common situation, where everyone is discussing something and then staff says “send me the file”, and there is sensitive information. A private message (regardless of how it’s created) breaks the workflow, makes the topic harder to understand since some posts are “somewhere else”.