I thought she was just a goofy little preteen hamming it up for her friends at home.
She did it from the beginning of his speech when he was introducing his family all the way to the end.
Can result in embarrassing still shots of Trump with this airhead behind him.
I could see doing it once or twice for the thrill of being in the background, but it seemed she was on her phone constantly and posing for her different friends. They were probably asking her to do those weird poses.
It was very distracting—at least to me.