Tbh, Ive used skybox for I think 7 years now? I keep the screen mirroring button off and if I see its turned on I turn it off again. I dont even know what its for and why I would need it. There is not good explanation anywhere either that I have seen. A lot of the other features of skybox seem intuitive and obvious but I still dont know what the use of screen mirroring is.
Again, if I turn on screen mirroring, I have no idea what it actually did cause nothing seems to change anywhere.