I think there are two angles to this: the driver uses his/her lights (lamps) to illuminate the route ahead, and to indicate intention to stop or turn.
But other road users should be considered. One's lights(lamps) should never put other drivers at risk of reduced visual capacity by being blindingly bright or of too distracting a design (ie the Union Jack things)
Driving at night along our pitch black Norfolk roads, one sometimes meets a twit approaching with full beams, of that intensely bright bluish sort, and it does leave an after-effect for quite a time on the retina.
Use the dip switch please!
A vehicle isn't a bling-bling toy to jazz up like a Christmas tree.
I agree with you Gurney, and there should be tighter regulations about these things.