Are you talking about using "Brand Names" and "Keywords" as anchor text here?
If yes, then the answer would be this:
SEO is not just promoting websites for certain keywords on search engines, but also to build brand online. People who want their websites ranked for certain keywords on any search engines would use keywords as anchor texts and whoever want some popularity for brand, they would build anchor texts with brand name or website domain name.
I hope this answers your question.