Why? I never need to see my license plate when I ride, so I am guessing the stock bulb does a fine job. Beyond that, headlights light up the license plate quite nicely as well.
Well, there are two schools of thought regarding a brighter plate light:
One would be that ANY additional light on the bike makes it more visible, and that is always a good thing for safety. The other would be that if the light is really bright, it has the opposite effect- making the plate somewhat harder to read... which might be useful for those trying not to make that function easy.
Also, replacing any incandescent light with an LED will save power that could be used somewhere else, or drain the battery less when the alternator is not turning, or speed up charging when it is running. Also has the potential to burn out less (but they are also typically color challenged, expensive, have viewing angle problems, and are often dimmer).
That said, I think it would be far better to add more red taillights to make the area of light in the rear larger.
