The the_author() function is used to display the author of a post. By using the_author(), developers can dynamically display the author's name without manually inputting it for each post. The function fetches the author's name directly from the WordPress database, ensuring that the correct author's name is displayed for each post.
The the_author_link() function is used to display the author's name as a link to their archive page. This is useful because it creates a more interactive and user-friendly experience for website visitors by allowing them to easily access more content from a specific author. This function does not accept any additional parameters, it is a simple function that does not require any additional input to work.
These two functions have a couple similarities/differences. They're similar in the way of being used to display the names of the author who wrote the post are typically used within The Loop in WordPress themes. They differ in that the_author() displays the name as plain text, while the_author_link() displays the author's name as a link to their archive page where users can view all posts by that author.
In summary, these two functions are very simple, and easy to use. They are beneficial because it keeps developers from having to enter author information into WordPress site's manually. Having author information, and their history of posts, help make your WordPress site more of a user-friendly and interactive experience.