Also it could just be Molag Bal being a dick, daedric curses tend to have symbolism behind them. For example if memory serves right the reason werebeasts transform at night is because Hircine is honoring Lorkhan/Shor/Shezar who’s corpse is the moons, but not the necromancers moon that’s manimarco the god of necromancy.

I always assumed they prefer dark spaces because they have permanent night eye.

Like Riddick