Sketching by hand provides a free-flowing experience outside of the constraints of digital. Whether I choose graphite, charcoal or markers, the end result tends to be more organic and "perfectly imperfect" compared to a digital illustration.
Digital illustrations are better suited for rendered artwork, such as an infographic summarizing a finite set of data. These graphics can be beneficial to businesses wanting to visually represent statistics and value to a customer base such as a "year in review" targeting stakeholders.
There's nothing like a pop of movement on your website to help direct a user's attention to a call-to-action, or a subtle motion to excite and delight customers to keep their interest as they continue engaging with your content! The good news is modern front-end languages including HTML, CSS and jQuery can each uniquely support animated web elements for these purposes without the need for high-res video.