I'ts a little bit complicated. Following your example, I think there's room for a debate.
As my experience in other MMORPGs, I think more important than the number itself is an simple indicator to the player telling if your damage is below from the required for that content, just the minimum for, or far more. It could be just a simple color, 5k red is bad, 5k damage yellow is average, 5k green is a lot.
And thats true. I'm reallly don't care about anything lol. I spent 5 minutes looking for a longbow ranger build in 1012 and never changed it. At least my gear is my crafted exotic berserker. It's been a lot of years haha. I just made the mandatory... strikes was it? from Icebrood saga for the story. back in vanilla cleared all dungeons and paths one time and thats it. I only play for the map completion and story.