It's information I've researched (as always do before replying, unless I know for sure already).
The switch doesn't do anything to the motherboard BIOS. It simply flips the VBIOS of the card to be compatible with whichever BIOS type the host motherboard has (ie legacy or UEFI).
The VBIOS switch is unique to some 750 Ti cards and is an officially undocumented feature it seems.
Of course there will be switches on other graphics cards but they will perform totally different functions such as those you've mentioned.
I hope this clears things up.