The importance of having a blog.
Having a blog is another way to bring people to your website and to informally show them the processes you use to create your art.
It also gives you more space to tell the story about your work: why you've chosen a particular title, the materials you've used, the inspiration behind the art, if it's for a private collection, a commission piece or an entry into a galley (and which gallery).
A blog is one more page that will show up in search engines. It also gives people the opportunity to share your post on all social media outlets. Keeping your website fresh with a new blog post occasionally, will keep people visiting your website.
Blog posts are the ideal home for internal links which make your post more authoritative and useful to your readers. They also give your search engine results a rankings boost.