When WordPress was first introduced, it revolutionized the way people built their websites. Rather than having to learn HTML coding or settle for a WYSIWYG web page design program that seldom worked as advertised, website owners suddenly had the choice to use a content management system that could be used to create fully functioning and professional looking websites with very little effort.
One of the keys to the success of WordPress is a design based on the concept of dynamic web pages. And by the way, WordPress pages and posts are dynamic despite the common misconception that they are static. That misconception is due, in part, to the recommendation that WordPress users utilize child themes. Allow us to explain.
A static web page is one that is built with HTML that is confined to that one page only. The website designer intending to create a multi-page site with identical theming still needs to create a separate document for every page on that site. A dynamic page is the complete opposite.
Dynamic pages use a general theme controlled by a CSS template applied uniformly to every page on the site. Page content is stored in a database and retrieved only when needed. This arrangement allows the developer to create the user interface once for every future page and post. Only the page content must be generated as needed.
The Question of Child Themes
The understanding that WordPress pages are dynamic may have you wondering why so many WordPress experts recommend the use of child themes. After all, if theme elements are generated once and then applied to every page and post as needed, there shouldn’t be a necessity to create a separate child theme. But still, there is.
If a website owner deploys a theme without any modifications, no child theme is necessary. A child theme is necessary if a website owner wants to protect modifications from being overwritten on the next update.
For example, let us assume that the main font for your chosen theme is not acceptable. With a simple edit to the appropriate CSS file, you can change the font to something you find more suitable. If you do not use a child theme, your site will revert to the old font next time the developer updates the theme. You would then have to go back into the editor and make your changes again.
The advantage of child themes is that they are not subject to developer updates that would affect your modifications. Using a child theme would let you change the font once and then forget about it.
WordPress pages and posts are dynamic in every sense. We only recommend child themes because modifications can be affected by future developer updates. Those modifications and updates have nothing to do with the fact that WordPress uses dynamic pages and posts. If you want more details on the topic, the official WordPress documentation explains it all thoroughly.