Why not? As far as "looking for something to do", preserving a dying language seems a lot more interesting than a lot of other things people do with their spare time.
At one point I used to think that language diversity was actually a net bad thing for humanity, because it decreases our ability to communicate and so on. These days language technology and machine translation are solving that communication issue and we may choose to preserve dying languages for the sake of understanding how language itself works, how humans migrated in the past, and so on.
Learn one, and you are partially learning the other.