That's a strange question but a legit one. I was taught if it's there it has to work properly. I would say that's 50/50 depending what leo you run into. They have standards how far they must be seen from. Losing some of the LEDs lowers that distance. It's on it's way out so just go ahead and replace it.
That's about 100 pages just on the light bulbs. The best I can tell the photometry has to be so much luminous intensity. Sorting through the maze I think I interpreted 5 times as bright as the tail lights and 60% of it's luminous intensity. First you need a photometer. Don't hold me to it. You can read the mess. I rather buy you a bulb!