It "works" in that it will display a signal on a VGA monitor... but the RF and compo%&$#?@!%&$#?@!%&$#?@!%&$#?@! work too....
I have two Amigas, a Sega Mega Drive and Super Nintendo, all of which I would like to connect to a modern TV using their RGB output, and I still wouldn't use a GBS for this, and I already own one!