@reyalp, I had more time to look into this now.
It works in the sense that it can decrease exposure while recording video, but it can't
increase exposure (something I never use it for).
The horizontal exposure level that appears on the screen when
you press the +/- button to activate this, never goes passed the middle to increase
exposure, in other words, it never goes into the positive steps that the exposure level displays on the screen.
It is fine with me if it is removed since "Enable Fast EV swit [.]"
can accomplish the same thing while recording video. But it won't
display any horizontal exposure level to indicate the steps of
exposure. However, you do see the screen getting darker/lighter when
you press the up/down buttons.
If it can save some memory or simplify code, it is fine to remove it.