Bitcoin mining is completely optional. You can trade bitcoins for real currency, buy and sell stuff with bitcoins, etc., and that has nothing to do with mining. Mining is basically a lottery where you donate tons of your CPU. If you win the lottery, you get a few bitcoins, and in the process you and all the other miners are helping preserve the integrity of the bitcoin transaction history.

As to the concern about bitcoins being independent of any sort of central bank, we already have many currencies that have this property: precious metals, land, etc. Bitcoins have the property that there's a lot less friction in the buying and selling, which is a good thing. All the other downsides, though, are pretty decisive. What the world really needs is not bitcoins, but rather cheaper credit cards (from the merchant's perspective) while retaining all the insurance and other benefits.