Disclaimers protect you, the business/website owner, by making it very clear to your users that you will not be held liable for certain things. For example, if you run a website that discusses health topics, having a disclaimer that states that you're not acting as a doctor to your readers, and that all information must be used at the reader's own risk makes it clear to the reader that no doctor/patient relationship is formed, and that it is not your liability if your website content doesn't help them personally.