Here's why:
* Articles are generally considered shorter works, often part of a larger publication (like a magazine or newspaper).
* Quotation marks are used for shorter works like poems, songs, articles, short stories, essays, chapters of books, and episodes of TV shows.
* Underlining is typically used for longer works, like books, plays, movies, and albums.
Example:
* I read an interesting article titled "The Future of Artificial Intelligence."