It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout. The point of using is that it has a more or less normal distribution of letters, as opposed to using Content here, content here', making it look like readable English

Many desktop publishing packages and web page editors now use placeholder text as their default model text. This makes it easier for designers to focus on visual layout and composition before adding the actual written content that will complete the final design.

Using sample text allows readers to imagine how a finished page might look once the real words are placed. It helps maintain balance in the layout and ensures that the design remains visually appealing, regardless of the amount of text used later.