It will become obsolete. As for a store of value, it depends on enough people wanting to buy it.
Now, why would anyone buy it? That's the question.
Because it retains its value. Because its value isn't impacted by country or geo-political risk. Because its supply is finite (once mined). Because its supply isn't influenced susceptible to nefarious manipulation. Because Casascius coins are shiny like gold!
If we ever agree that it has no value, it will have no value. Just like the Dollar...the only reason it has value is because we all agree that it does.