Is it something you use?
What would you think about removing it?
I don't use it, and never tested it :( ... looks like it does work though :D Depending on the topic and site it can add a bit of server load I would think.
On occasion I use it. Mainly when I'm looking for something in the topic using my browser.
So to use the search function of the browser?
Mainly, yes. Also, when a site loads slower than my connection or when it is image/photo heavy, it helps to load "all" so I can do other things while the entire page loads.