What is a benefit of deleted text

Answer 1

Consider Stackoverflow for example. When you edit your post, complete edit history can be seen at anytime from then. If you deleted anything while editing, that's put inside <del></del> in the edit history. Well, this is a benefit of deleted text.

Answer 2

If you have a website that changes a lot, and you want to show everyone the things that you deleted and replaced, use the <del> and <ins> tags. Other than that, not much, but I've seen websites use the <del> tag for humorous purposes. It really depends on when you need text with a line through it.