1. Don't lump "to dark to see/align the sights" with "pitch black". There are periods of time and conditions during the night that you can identify a threat but not be able to line up regular sights.
2. If it's shooting at you, it's a threat and being able to line up your sights is a good thing.
Like having an extra magazine or three. Just because the average gunfight lasts 2.7 rounds (old number, I have no idea it that's still the statistic or not) doesn't mean you only need to carry 3 rounds in your pistol and the rest are useless. You have the extra rounds/magazines because conditions may result in you needing the additional "help."
Yeah, they've got to be lit up first but I'll have a flashlight with me anyway. And it really doesn't take much to charge them up. While I may have the flashlight in one hand, I may not be able to keep it on the intended target unless things are over, real quick.