Even thought the master KB for updates still says that they wont do this:
Seen on Edge, Front End, stand alone Mediation and PChat servers.
A change in policy at Microsoft or someone messing up?
If you do try to install this way then you're going to get a nice error as the CU (as usual) requires that the SfB Services are stopped:
If you do stop the services (Stop-CsWindowsService) prior to running Windows Update, then the update will pop the installer window as if you had manually downloaded the update:
As there is no database update since .281 maybe this is an okay way to install the updates, but just remember to restart the services afterwards if you are not going to be restarting the server!
To be honest anyone who wants to have control over the deployment of the CU wont be allowing this anyway as they would control via WSUS/SCCM etc.