What is the significance of using comments in HTML and CSS?

Using comments in HTML and CSS is significant primarily because they serve to annotate code for clarity. Comments allow developers to leave notes and explanations within the code, making it easier to understand the functionality and purpose of specific elements or styles. This is especially useful in larger projects where multiple developers may be working together, as comments can guide them through the rationale behind particular decisions or coding structures. Comments can also assist in debugging by allowing developers to leave reminders or temporarily disable certain code sections without deleting them.

While providing metadata for web pages, injecting JavaScript, and formatting the document visually are important aspects of web development, they do not pertain to the function of comments. Comments specifically focus on documentation and maintaining clarity in the codebase.