I think the main reason is to give busy bodies something to complain about. My camper has blinds that close when I go to bed and then I also close my eyes. Thus, it's dark.. Unless a neighbor has a spotlight aiming at my camper I don't have a problem.
I do turn of my outdoor lights as it makes it harder for opportunistic thieves to see what I may have left out under the awning.
2021 Chevy Silverado LTZ 3500 Diesel
2022 Montana Legacy 3931FB
Pull-Rite Super Glide 4500