If it's not an issue to you, then the rule is pointless to you.
Two problems with a pointless rule: complicates things for all players (guaranteed that some will miss out on using the loophole and become annoyed, and guaranteed that some will make a mistake in deckbuilding and post illegal decks; drama ensues), and a pointless rule means the issue it intended to fix isn't fixed.
Hell, a third problem would be that the final result is just uglying up the duo you want to use, and nothing more. It doesn't even have to be the same deck; I can make craptons of wildly different Aether/Darkness decks that aim to do completely different, or even opposite, things.