WCWS- Does the Coach Call Every Individual Pitch?

So I’m watching the Auburn-Oklahoma game (great finish, BTW), and I see the OK coach with a hand up. The assistant is holding a white panel behind the coach’s hand (I presume for visibility) and she flashes (and mouths) “5-5-3.”

They switch the camera to the pitcher, who is checking a wristband (looks like a QB wristband with a graph of sorts in it). Pitcher finishes checking the wristband, sets, pitches.

It looked for all the world to me like the coach was signaling to the pitcher what to throw, rather than the catcher/pitcher figuring it out between them.

Is this indeed so? If it is so, why? Can’t the pitcher and catcher figure it out? Shouldn’t that part of the game that the players make those decisions?