The primary advantage of using a content delivery network (CDN) for websites is improved performance and reliability. CDNs distribute content across multiple servers located in various geographical locations, reducing the distance data must travel to reach users. This leads to faster load times and a better user experience, especially for sites with high traffic or global audiences. Additionally, CDNs provide enhanced security features, such as protection against DDoS attacks, ensuring that content remains accessible even during peak times or in the face of threats.