Perhaps I am misunderstanding your statement.
That everything which born have to die as well.
It sounds like you are implying that we as humans have to die as in we must die in order to enjoy life now.
Like you said yourself, you misunderstood my statement. What I mean is that understanding the mortality of human animal helps us to enjoy our lives as much as possible here and now. Cause we are not living in spiritual pipedreams about heavenly glory or eternal existence, we realize that this is our day of glory and do the best we can to enjoy it.
Dreaming of rebirth, eternal life or heaven easily turns our minds away from this moments reality which easily turns us away of living fully now. For that reason I think it is more useful to live now than dream of future where to live!