It is used as a place holder for text. The first paragraph in the lesson says “ Web developers traditionally use lorem ipsum text as placeholder text. The lorem ipsum text is randomly scraped from a famous passage by Cicero of Ancient Rome.”
Maybe you are working on a project, and you’re not sure what the text is going to be, but you still want to see how everything looks with text. Thats just what it is, a placeholder so you can replace it with the correct text eventually.