Earlier quoted context omitted.
Sisyphus may disagree. :) * https://en.wikipedia.org/wiki/Sisyphus
If I was Sisyphus and got the boulder to the top, I would push it back down myself. I'm going to die eventually, so is it futile to exercise everyday, to learn, to try and be a better person? I don't think so, but all of those things are journeys that never end and require many mundane tasks.
Many repetitive activities end up having a practical purpose: as someone who does strength training I know about sets and reps and lifting heavy things. But that gives me strength for everyday things.
But the point of giving Sisyphus that task is precisely because it is pointless. Sisyphus isn't doing anything with his existence except that task.