why does the quarterback have to call the play at the line if they’ve discussed it in the huddle

Question

So, notwithstanding an audible where he’s changing the play, what else is there to announce?

In: 1

Answer 1

At the line, the QB is calling out the defensive positioning a lot of time (so the rest of his team knows what defense is being run), as well as distracting the defense on when they are going to snap the ball