Then, Other night thingies would be a boon
Which may be part of the reason they decided not to do a cosmetic day/night cycle. There would likely be a bunch of people with a couple reasonable suggestions (or complaints) each, which would add up. Even just the basics of a day/night cycle is not a trivial amount of work.
Of course a day/night cycle would have gameplay value, even if it was purely cosmetic. I was a little iffy on NPC schedules from the start (good for immersion, possibly annoying if you want to trade/talk to a particular NPC and it happens to be past their bedtime), but was looking forward to the phases of the moon having an influence on magic, etc. Even much less ambitions day/night changes could have a nice impact on gameplay.