[majormajor]

Yeah, that looks like it's simulating the rolling lines that could show up in a video of a CRT, which is just an artifact of the camera and display both refreshing in similar fashions/at similar rates but usually not being locked to each other. A similar fixed lined/brightness gradient on a still photo is an artifact of a snapshot vs the persistence of vision effect that makes the screen look uniformly bright.

Some people were more sensitive to CRT flickers than others but it didn't look like that, even at 60hz (a low rate for a PC monitor). It was more a flashing-the-whole-screen-on-and-off-constantly effect; the effect of moving lines in videos move far slower than 60hz.