Having full root-level access means that you can access and modify any kind of file on a specific server, which includes all system files, and to change system settings or install server-side software which may be necessary for certain scripts and even offline applications in order to work efficiently. A server is accessed at the root level with a root user, who has full privileges to do all the abovementioned tasks. Your root user may also make other users. For safety reasons, you're advised to have a different account for routine tasks and to use the root account only if you actually need to perform a specific task on your hosting server. The root-level access feature provides you with full control over your server from almost any location, given that you have the user credentials.
