Markup languages like HTML are essential for web development because they provide a standardized way for browsers to interpret and display content. While graphical software like Dreamweaver can simplify the process by generating HTML, the underlying code remains crucial for browser functionality. Even with WYSIWYG editors, understanding HTML is necessary for professional web developers, especially for dynamic applications. Markup languages facilitate the formatting and structuring of documents, enabling effective data transmission and storage. Ultimately, without markup languages, web browsers would lack the ability to accurately render content.