Dynamic websites built with PHP and a MySQL database offer a richer user experience compared to static sites. PHP, a server-side scripting language, handles the website's logic and interacts with the MySQL database to store and retrieve information. This allows for features like user logins, personalized content, and e-commerce functionality. When a user visits a dynamic website, PHP processes the request, fetches data from the database, and generates HTML that is sent to the user's browser. This process happens in real-time, making the website interactive and adaptable to user actions.