In my experience working with developers, we are frequently making updates on the fly, refreshing our browsers and not seeing the changes propagate on the screen. We'll go back over and over again and clear the cache and destroy the web data hoping for the changes to finally show.
But obviously I don't want to destroy all of my cache / web data. It'd be awesome to just be able to dump the cache to the specific url or domain that we're working in. All in a quick keystroke. It could be implemented through the already set options on safari or chrome for clearing the cache, but make it specific to the current page.