I now see some holes in my Apollo analogy (also government vs individual spending). I am lucky there is always someone on HN who will make a better point :)
Bitcoin gives users a trustworthy decentralized store of value today that they could easily move to another cryptocurrency in future using some kind of decentralized exchange based on smart contracts. It provides liquidity for all future cryptocurrencies.
The Apollo argument was more compelling because it didn't require any value-judgement of the end-goal (but it was less appealing to me for the reasons I outlined). It is an argument about the process, regardless of the results (in the end, the lunar landings in themselves were a symbolic victory more than any great advancement of science - the science happened on the way).
We can go into arguments on why I think the end-goal of crypto-currency believers a la Satoshi would be a net negative, but others have covered it pretty well (deflation, fraud, money laundering, having your life savings destroyed by a hack etc).