CMS helps to separate design of web site from its content. It means designer develops a web site and gives it to its owner or manager who can fill a certain design with different content. If necessary the content of web site, its images and graphics can be easily edited without intervention into design of web site. All changes become visible as soon as you make them. (Don‘t forget to reload page after making changes). Even if you are not an expert of HTML coding, you can easily manage the content of your web site yourself.
I would say the number one benefit to website templates is that they‘re going to save you from having to wait for somebody else to get done with your website. You won‘t control don‘t you? Well website templates allow you to have a personal website set up within a few days after purchasing. All you would need is to select the platform you want and then choose templates that are going to suit it. Now compare this to trying to do everything yourself or hiring a professional web developer. It can take days before the product is even ready to get started.