Bullshit. We don't know how long life lasts, nor whether supernatural purposes or intentful[0] beings exist, nor what (if anything) is after. That does not mean there is "no purpose" to it. It is its own purpose.

Personally, I am most in line with Buddhism and think reincarnation is likely, and that mind (consciousness) itself is a first-class citizen, but existence doesn't have to be eternal to be meaningful. In fact, if a finite existence were meaningless, then an eternal one would be meaningless and infinite, which would be far more undesirable than death.

[0] "Intentful" is not a dictionary word, but nothing else captures what I am trying to say so I am justified in making a word up.