Well, to that, I can only quote:

> If you don't know the future, how do you know if what you do will or won't matter in the grand scheme of things? How do you know if you can even properly conceptualize "consequence" or what "matters" for your future self?

:-)

There's little semantic difference between "hope", "know what will", "think that's worth a lot", and "predict" in this future-facing context.

(Note that I'm not promoting nihilism here, only pointing out that what you state against nihilism actually applies against many things broadly, in the exact same way, to the point where it could easily be used as a pro-nihilist argument.)