There are several reasons why WordPress is a popular choice for building websites:

1. It is easy to use: WordPress has a user-friendly interface that makes it easy for beginners to create and manage a website, even if they have no coding experience.
2. It is flexible: WordPress is a highly customizable platform, with thousands of themes and plugins available to add functionality to your website.
3. It is SEO friendly: WordPress is optimized for search engines, which can help improve your website’s ranking in search results.
4. It has a large community: WordPress has a large and active community of users and developers, which makes it easy to find support and resources for your website.
5. It is mobile-friendly: Many WordPress themes are designed to be responsive, which means they adjust to different screen sizes and look good on mobile devices.
6. It is well-documented: WordPress has a wealth of documentation and tutorials available online, which makes it easy to learn how to use the platform.
7. It is widely used: WordPress is the most popular content management system (CMS) in the world, with a market share of over 60%. This means that it has been tested and proven by a large number of users.

Overall, WordPress is a popular choice for building websites because it is easy to use, flexible, SEO friendly, and widely used. It is suitable for a wide range of websites, from small personal blogs to large corporate websites.