A picture paints a thousand words!
Websites are visual representations of your company. Granted it needs to have the information your site visitors are looking for, but reems of text can be confusing and key points you are trying to make may be lost.
Illustration can be used to provide decorative elements to your website, and can often portray a point more effectively than a photograph. Sometimes, photographic images just dont exist or you cant source one.
Infographics are an illustrative diagram that allow you to present often "dry" information, such as statistics in a more interesting and palatable way. They provide an easy way to learn about a topic without a lot of reading. They can be used to educate and inform. A well designed infographic can be used to build brand awareness and build inbound links.
The ultimate goal for an infographic is to be shared.