It definitely affects the power draw. Even more than presets with different CPU usage.
Here is the old video that shows similar measurements to what InGainWeTrust reported (1.74A on boot and around 1.2A with low brightness and different presets).
Around 01:40 they put the maximum brightness to 100% and the current peaks at around 1.7A.
Would be interesting to know if that maximum has increased since 2021.