On the meta side, it's making yourself a target, which you can compensate for per above, or doesn't matter if you're the high priest amid your congregation.
On the in character logic side, to me, it's like going full OB in physical combat. . .when you declare all out gestures and shouted incantations, you're screaming it out, jerking around, doing it fortissimo, putting your full effort into it without restraint. . .