Having full root-level access means that you will be able to access and modify any file on a specific server, which includes all the system files, and to change system settings or install server-side software which may be necessary for certain scripts and even offline applications to function effectively. A server is accessed at the root level with a root user, which has full privileges to do all the aforementioned tasks. Your root user can also make other users. For security reasons, you are advised to have a different account for day-to-day tasks and to use the root account only if you actually need to do a task on your hosting server. The root-level access attribute will provide you with full control of your server from any kind of location, given that you know the user credentials.