Say you're Elon Musk, billionaire and really smart guy. And you're asked to give a speech. That speech will be viewed by millions.
You probably have a speechwriter, and a PR consultant, and hey, why not a body language consultant. When you get on stage, you're going to present exactly the message you mean to. Anything less would be a waste of your time, right?
I don't actually believe this, but am picking an argument that I expect deadeye an Elon apologist to believe. If you don't think he's smart I don't need to convince you?