How can including files with the include() function be a viable alternative to using classes for organizing PHP code?

When organizing PHP code, including files with the include() function can be a viable alternative to using classes. This approach allows for modularization of code by breaking it into separate files, making it easier to manage and maintain. By including files where needed, you can reuse code snippets across multiple pages without the need for creating classes.

// index.php
include 'header.php';
include 'content.php';
include 'footer.php';