So let me present my past argument for this.
If we have the nights brighter where everyone can see, everyone is on a fairer playing field. There will be people who still turn up their gamma for clarity sake, but more people will be inclined to not tamper with the settings with it being brighter overall and it allows everyone to again see more clearly across the board. As some people will be not so tech savvy and wont understand or bother with turning gamma up because they don't know how or it's "too much work" (yes, they exist.) or some other reason.
Now, let us say they made it darker again. What's that going to do? Increase immersion? Sure, for a time. But people who PvP and want to find / see you, will still have their gamma jacked up via GPU, programs, monitor, etc. You're not going to hide from someone if they're truly wanting to kill you. So this doesn't work in the favor of most across the board, and it now forces players who want a higher survival rate to turn their gamma up as well now adding an extra unadditional step to their gameplay to play against other players.
Point being. Brighter nights is better because it actually keeps players safer, and lets immersion still exist to some extent but also allows a more so even playing field as opposed to darker nights.