WordPress speed optimization services take all the burden of analyzing your website assets, overall auditing performance, ongoing issues, and server impact on speed, and then fix them with their skills, experience, and setting up website cache. While speed optimization plugins make it easy to configure and automate many things for you, they can break your site design and functionalities. It does not mean the speed optimization plugins are poor, but if you want to squeeze out every bit of potential speed from the website, a speed optimization service is a perfect option. When you have a small site with no page builders and lower assets, try creating a staging version and then experiment with caching plugins, including other optimization plugins, with seeing what performance you can get.