Sleeping next to a bright fire though, is way more easy and cozy, than sleeping next to a bright LED flashlight.
The red light (and sound) of the fire has a very soothing effect, which has probably something to do that our ancestors slept next to it since ~1 mio years.
(it is still fun, just don't use a new sleeping bag, as it might get holes)
I'm glad our ancestors were less worried about the quality of their sleep and more worried about what beasts might attack them during the night and using fire to keep them away, otherwise we may not be sitting here discussing how LED lighting impacts sleep quality...
actually, infrared light from campfires improves sleeping quality because it triggers melatonin production in the brain. In contrast, blue bright light triggers cortisol production.