Without IIS performance monitoring, you could end up leaving your site (and your users) hanging. At best, this will leave a bad taste in your user’s mouths. At worst, they’ll stop using your services.
Everyone wants better performance and response from web applications. These days in web applications, performance is very crucial from a user and business point of view. Web Servers are easy to set up when things are small, however it’s extremely difficult to set up when things start to scale.