Simply annoying, more if you like to have the taskbar at the top of the screen. I like to have it there in my little Thinkpad.
I SOLVED it by renaming a file in c:\Windows\System32 named Windows.Internal.PlatformExtension.MiracastBannerExperience.dll
I've had to change the owner of the file from its Properties->Security->Advanced options->then at the top change the owner, next give permissions to Administrators users, and change the file extension to .old.
I've had to reboot for this lovely hack to take effect. I connected again to my Samsung wireless TV and no more stupid banner.
I don't know if this is a good advice but I've got rid of it. I'm a simple user and won't be responsible if you burn your TV or Mars changes its orbit by renaming that file.
Please excuse my poor english.
MS please, why you call EXPERIENCE to things like this? If you add something to our work space, please let us disable it!! Or put it SMALLER.
Regards.