We've seen before in Game of Thrones season 8 that the army of the dead and the white walkers are destroyed but in the season finale, Jon is sent to the wall to be a Nightwatch again.
But why does the Nightwatch still exist?
What exactly do they "watch"?
For quite some time people had ceased to seriously believe in White Walkers. During that time the Night's Watch continued to exist, serving two purposes:
No reason it can't continue to do this. The first one is all the more relevant now that there's a big hole in the wall. And there's a shot at good political relations with them now, which would transform the first into the political function of preserving and monitoring those relations.
The White Walkers were thought to be a myth until they appeared in real life. The Night's Watch could defend against the possibility of other mythical creatures being real.
Tryion speaks of "Grumkins and Snarks".
