Group "Announcements" Actually Notifying Members

I don't really understand how this isn't vanilla mechanic.
Why is it called a "group announcement" if nothing is being announced?
I want two things here;

1. the ability to let my members know we're holding a giveaway, event, raffle etc with the "announcement" posts.
and
2. The ability for members t "turn off" the pings because I have to be on both sides of the scale here if I'm honest.