Performance is crucial for a web application because it directly affects user experience, user engagement, and ultimately, the success of the application. Here are some of the reasons why performance is so important for a web application:

1. User Experience: Users expect web applications to be fast and responsive. If an application is slow or unresponsive, users may become frustrated and abandon the application. A slow application can lead to poor user experience and user engagement, which can result in decreased user satisfaction and retention.

2. Conversion Rates: A fast and responsive web application can improve conversion rates by reducing the time it takes for users to complete tasks, such as making a purchase or filling out a form. Improved conversion rates can lead to increased revenue and profitability for the business.

3. Search Engine Optimization (SEO): Search engines like Google consider page load speed as a ranking factor in their algorithms. A faster loading website can lead to better search engine rankings, which can result in more organic traffic and higher visibility for the website.

4. Competitiveness: In today's digital age, businesses need to be competitive to stay ahead of their competitors. A slow or poorly performing web application can put a business at a disadvantage and make it harder to compete with other businesses that have faster and more responsive applications.

5. Scalability: Performance is also important for scalability. A well-performing web application can handle more traffic and users without slowing down or crashing. This can help the business to grow and expand without needing to invest in expensive infrastructure upgrades.

In summary, performance is critical for the success of a web application. It affects user experience, conversion rates, search engine rankings, competitiveness, and scalability. A fast and responsive web application can lead to better user engagement, increased revenue, and a more successful business.