Even if you are a startup currently in need of a simple website, you will have to scale up the site as your business grows. Aside from scalability, a content management system or CMS makes it possible to frequently update a range of content types from images to podcasts, and work with user-generated content such as polls or forums.
Though installation and configuration of a CMS initially involves the help of a developer, it soon transfers the control of content updates to content writers/managers. From a business standpoint, a CMS also minimizes cost of designing a website from scratch and does not require you to hire developers to manage your website.