I've been consistently watching her and I think that she only lips certain songs in concert.
From the I Am... Tour, I think it's only Naughty Girl, Freakum Dress, Get Me Bodied, and Single Ladies.
If you watch her, she innately knows to take the mic away from her mouth after she finishes a phrase so that she doesn't breathe into the mic. That's her knowing how to perform and the technical aspects of performing.
That's what makes her special.