Many people are under the impression that developing multiple pages with irrelevant content is a good long-term strategy for ranking many pages within the site well. This of course is a misconception that needs clarification. The Google webmaster guidelines specifically states not to develop pages for the sole purpose of search engine rankings.
Make pages for users, not for search engines. Don’t deceive your users or present different content to search engines than you display to users, which is commonly referred to as “cloaking.
– Google Webmaster Guidelines
It is true that websites with more relevant content have a higher chance to rank well, so it would be in your best interest to develop these additional pages if and only if the content is unique and relevant. The primary purpose of developing these pages should be for the users that visit the site and ultimately read your content.