Wordpress itself, and your plugins and themes regularly releases updates of themselves, and these updates fix bugs, security issues, and add new features. So it’s a good idea to stay on top of these updates for the health of your site and to minimize the change that your site will be hacked or stop working. Beyond that you might have content updates you want to do to your website to add news, events, new products, etc… and Kate can take care of that for you too.