Given that it's scanning the duty cycle as seen by any part of the eye is very small. If the perceived brightness was a function of power density averaged over time, then it would very obviously have to be able to be much brighter than "full white" to create the full white experience[^].

[^] in reality the perceived brightness is somewhat higher than the mean (i.e. a light source that's twice as bright with twice smaller duty cycle appears brighter). I'm not sure how large an effect that is, and whether it has anything to do with pupil size adjustment.

> Picture your monitor going all white... bright for a sec, but that's about it

I remember when a CRT monitor would mess up and stop scanning right the white point in the middle was much brighter than the normal brightness, I was always worried it would burn in and would shut off the monitor right away