Building and using a prototype helps the team to envision how the site will look and work. Since a prototype is a working model of the site, it also helps to test early on all the site’s main interactions and elements. The prototype also helps to answer crucial questions that will play into the creative and design success.
This process helps clarify critical questions before design. e.g., Does the menu structure and location follow a user’s mindset? How is related content linked? Where is the essential conversion content placed?
By working with a prototype, you get to thoroughly test how your website will work without making determinations about patterns and color of buttons or any of the graphics.