This is a simple system that parallels the function of Departments. The only significant difference is that Brands are all at a single level (no sub-brands).
If active in your license and implemented as part of your design, users can navigate to a listing of all items by a particular Brand usually from a logo or a brand name listing on the Product display page. Combined with regular page elements like title, filename, and description, this can help boost your SEO and rankings for a particular brand.
Brand includes the SEO Download & Replace function at the bottom of the list on the landing page.