This is a type of button that will allow you to get to the website that would have been listed at the top search result. You are feeling lucky because you do not have to scroll through different websites and links anymore. You will be taken to the website that you want. When you want to bypass the search engine results page, this is the best button that you can try.
Who knows, you may be genuinely feeling lucky and you will find the details that you are looking for on the website that you will be redirected to. Millions of people use Google Search, but a few still use the I Am Feeling Lucky Button from time to time.