Depending on the goal of the storyboard, style can make or break the immersion. For this it is important to remain consistent in the format and look of each frame (similar colors, art style etc). Too much variation in the look of a storyboard and the viewer is pulled out of the story.
EXAMPLE 1 - Dark
He made his way to the house...
EXAMPLE 2 - Artistic
I am a happy cow, I love this wonderful field!
Experiment with what styles work for your story!
Think of what is scene in the viewfinder of a camera when recording. Only show what you want the audience to see. Elements: Muted Colors, Artistic fonts/boxes
By putting different types of images (drawn and photo) in the same scene a unique look is achieved. Elements: Contrasting imagery