Not that I think it should be disallowed, but... would it really "help with accessibility"? In what case would a black/white game be less/more accessible than a red/blue one? Or a pastel pink/pastel yellow one?
some people find very high contrast colours (such as solid black and white) hard to look at, and I imagine this is made worse if the colours are also flashing.
Ah, and colors with less contrast to each other could remedy that. I see.