Having full root-level access signifies that you can access and change every file on a selected 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 apps to function appropriately. A server is accessed at the root level with a root user, who has full privileges to perform all the abovementioned things. Your root user may also make other users. For security reasons, you're advised to have a different account for routine tasks and to use the root account only if you actually need to do a task on the hosting server. The root-level access feature offers you full control of your server from any kind of location, given that you have the user credentials.