1. Compressing CSS code can greatly reduce the size of web pages and speed up web page loading.
2. Js/Css files are large. When users visit the site, it takes a long time to download Js/Css and it will feel slow. In some cases, the initial opening of the page is even messy due to the Css files.
3. We cannot change the user's network conditions. We can only use faster bandwidth or stronger servers on our website to make users feel faster when they visit us.