The license is not a fiction. It grants you powers that you would otherwise not have, only holding the installation media. For example, it grants you the right to make copies of the software - usually one for installation, one for execution and one for backup.
It does not, usually, grant you permission to make additional copies for execution on other computers (without deleting the first one).
Your use of this software is not limited by the license, it is extended. Without a license, installation media for copyrighted software has no legal value.
