IMO, I think there's no need for Ethereum to have an additional token, they should remain as one, if the PoS is better then thats it, by the way, Im just thinking in advance because it is not clear yet if the merge will result in a creation new token but I strongly believe it's not the intention. Binance is always shown compassion to mitigate the possible scenario if it gets complicated.
Its just a provision for any mistake in the merger, this could lead to protecting coin that are safe during process and leave those with mistake out, This happen on blockchain often during such development and it is not new, they call it the hardfork. ETC is a result of an hardfork though they didnt plan it either.