Or after so many years in the film industry, you consider your brain sufficiently messed with?

LED's can be dimmed using PWM on/off frequencies and by constant current reduction. The latter is completely analog like dimming an incandescent. The PWM dimmers operate at frequencies >200hz, so unless one is doing rapid motion, this should be completely unnoticeable even by your subconscious brain. Film flicker is much lower speed than that.

Of course, cheap dimmers will be the worse.

As for reading lamps, I don't really see the point of dimming. Just buy bulbs with the amount of light output comfortable for reading use.

Mark