It is true that, nowadays, you can earn money by trading some bitcoin. However, by its nature, bitcoin is not something like that at all. Satoshi Nakamoto, its creator, has invented the system of block-chain as a way to make it possible a peer-to-peer payment system on the Internet without third-party organizations. Thus, for bitcoin to be a pioneer of a brand-new social model or to be something revolutionary, we should SEPARATELY consider bitcoin (and other virtual "currency") and currencies issued by nations.
That's really the purpose of btc but who won't grab an oppurtunity to make some money? Isn't it other local currency is being traded as well. Trading is also consider as a job because you are putting effort and making money out of it. We can't also stop people think of btc as a way of making money because many have earned decent amount just from btc and it has been practiced since then.