Sure you'll see the increased lens flare, to the degree that your display can reproduce it. If your monitor is already set to be too hot, then an increased lens flare will appear even hotter and may even clip. Or if your monitor is set to be too dim, the increased lens flare may still seem diminished.
Abrams knows that the lens flare he just created in that editing bay is exactly what is going to be represented in the files. The thing of it is that he can't account for consumer displays that don't have near the accuracy tolerance of his Sony X310 (X300, hopefully). The inaccuracies of our consumer monitors could make the lens flare brighter *or* darker. So start off with the most accurate point possible to accommodate the highest number of variables that could occur on our meager displays downstream.
In your Game of Thrones reference, I could see the night battle just fine on my loosely-calibrated LG OLED. My issue was with the horrendous compression more than it was with the darkness. So when I woke up the next day and saw all the complaints about the darkness I was a bit confused until I dove in and read about it more.