Most users will (rightly so) view this as an OS upgrade, not as an update. You already gave MS permission to provide you with security updates. You did not give MS permission to upgrade your OS. I feel the difference is of importance as updates are often necessary, while upgrades are not.
This update installs the Get Windows 10 app, which
helps users understand their Windows 10 upgrade options
and device readiness.
https://support.microsoft.com/en-us/kb/3035583