One thing a storyboard can’t do well is timing. All the shots might work as stills, but when animated, might be too long or short to go with the soundtrack. The animatic works as a rehearsal for the the film. A good one will allow everyone to see if the final film will meet everyone’s expectations, and hold the audience’s attention.. It will help avoid potential misunderstandings about camera moves, poses and action. And it allows the animators to concentrate on getting the best performance out of the characters at the next stage.