to update the memory cache to get latest value
We update the memory cache in order to get the latest value. RAM needs to be refreshed so that it retains the data for a longer time. As for web pages the data is stored in the cache, and refreshing the web page updates the cache with new set of information or values and the latest information is viewed.
When your first go to that web page, it takes a lot of time to load, that is because it is saving the page in something called your cache. When you next visit the page, it loads the stuff in your cache. If something is changed on that web page, your computer doesn't care. Until you refresh the page. It wipes out the cache, and re-loads the page with the new content. That's why if you don't refresh pages, you get the old stuff