Why is matching page titles, link text and file names important for Search Engine Optimisation?

Search engines reward web sites that they feel are more user friendly. In matching your link text to your page titles and file names, navigating through your site, from a users perspective, becomes very clear.

For example SiteA uses the link text contact a search engine optimisation consultant to link to their contact page. A good page title for the contact page would therefore be 'Contact a Search Engine Optimisation Consultant'. It would then be beneficial to name the file for the page contact-a-search-engine-optimisation-consultant.htm.