No day/night cycle doesn't mean it's an eternal day in the game. You camp at night, so most of the stuff in the camp is probably during evening. You could get ambushed, thus fight during the night. There could also be quests where some events such as mounting an offensive against enemy fortress could be at night etc.

I do admit it's a bit of a bummer not to have it, but it's hardly a deal breaker. There are pros and cons either way.