Is crying powerful?

Have you heard of The Great Pottery Throw Down? It's like The Great British Bake Off - but with clay. It includes a judge called Keith Brymer-Jones, who in every episode starts to cry or get choked up at least once, and it’s become a bit of a thing. He cries when he feels moved by something in a good way. So, what about crying? And can it ever be positive, especially in public?