It's a red flag to me when people close all their apps. It shows that they have unlimited data and a huge battery. It uses less battery and data to keep them open. Rebooting an app every time consumes more data and CPU cycles.
As someone with "Eh, it's alright" eyesight, I looooove dark mode interfaces. I can keep stronger contrast from increased brightness without getting melanoma on my face. In a room I'm around 70% brightness and it's still nice and dim.
A bulb is like a thin lamp that uses legal magic. A parchment is like a thin tablet that you can also use for wiping poo off your bum, depending on the author. They probably don't have these below the Cloud District.