Having full root-level access means that you'll be able to access and update any file on a specific server, which includes all of the system files, and to change system settings or install server-side software which may be required by certain scripts and even offline apps to work effectively. A server is accessed at the root level through a root user, who has full privileges to perform all of the abovementioned things. Your root user may also make other users. For safety reasons, you are advised to have another account for daily tasks and to use the root account only if you actually need to perform some task on the server. The root-level access function will provide you with full control over your server from almost any location, as long as you have the user credentials.