Using the Grid is key to making any publication look professional. It creates a template for any other elements such as, titles, images, or page numbers to be laid out in. Allowing for elements that need to remain consistent to appear in the same place across all the pages of a copy.
“Central to most modern magazine design is the grid – which has become almost synonymous with the professional approach. The purpose of the grid is to provide a basic template that will enable consistency across the magazine.” 
Here is an In design document created with a basic template. As you can see the grid has been used to ensure page numbers appear in exactly the same position on each page.
 Jason Whittikar. Magazine Production. (2008). Taylor & Francis Group. Page 138.