I've also thought about this question. For me, the day/night cycle works when it fits organically into the game world, rather than just changing the lighting. It's cool when different enemies appear at night, the characters' behavior changes, or new opportunities for progression open up. But if it's just a cosmetic detail, I quickly stop paying attention to it.
Yeah, but even then it would be a minor addition (and probably something TRIVIAL to add, effort-wise) rather than something actively detrimental to the game's quality and it would STILL open a lot of possibilities to modderns who want to leverage the feature.
So back to the point: no, even this won't be a sound argument AGAINST having a day/night cycle.
