Storyboarding is particularly helpful during storyboarding as a means of understanding and emphasising with a real world user problem.
By visually showing the steps a user takes to complete a task, it can help further build understanding in a very simple but quick way - aiding the ideation process during the ideation process.
Pioneered by Disney, Storyboarding pinned images to a board which then allowed for quick editing and changes of the shots during filmmaking - this same idea translates well to product ideation.
By visualising the steps a user would normally go through in order to accomplish a task, the problems they may face, or the potential user experience we are ideating for, we build empathy and understanding.
In this instance, we use it to help fill out the product after the initial ideation concepts / ideas / innovation has taken place - this will then also help inform the various user Flows as we move through the ideation phase.