I wonder if this ritual of meta-self-policing serves some particular purpose or if it's just a case of the brain drawing comfort from going through a familiar ritual. "This comment adds nothing" is like the reverse amen in church of our days.
It confirms for me that I too made the right choice and it reminds people that haven't made the jump yet that they have a choice in how their operating system treats them. I'd say it added a lot more than your comment.