"Why do anything?". Presented with these options, which would you prefer:
A. Live a normal life and be promised that after your death people will fabricate a story of your adventure, heroism and glory?
B. Live a life of adventure, heroism and glory with the promise that when you die nobody will remember you?
The point being, why derive meaning from the notion of being remembered by people you will never know, when the meaning may be found in the experiences our actions produce now?
The heights of human happiness (yeah, misery too) are ours for the taking. Derive meaning from trying to squeeze as much of the former from life as we possibly can.