Who is Valencia from Women and what is their importance?

Valencia is a typist. She writes letters to Henry and asks to meet him for sex. He agrees and they meet at a bar. Henry dislikes her immediately, finding her to be fat and unattractive. Nevertheless, they proceed to his apartment and have dispirited and mechanical sex. Valencia refuses oral sex and appears nearly catatonic throughout intercourse. Henry then drives her home where he goes inside, drinks, vomits, and then leaves.