Mining is just speculating on bitcoin in a different way. Right now you will at best break even mining, so by mining you are essentially saying that you think the price of BTC will rise. That is the same thing as simply taking the same amount of money and buying some BTC. However, with mining there is less of a trail to you of how you got your BTC versus an exchange.
I think it's more about the tangible assets that you can liquidate if the price falls.
If you buy a 12k miner today and the price falls by half tomorrow, you can sill sell that 12k miner for almost as much as you paid for it as long as you are reasonably quick about it before the machine values start to fall too. (Their value lags behind btc by 4-8 weeks)
If you buy 12k worth of btc and it falls to half tomorrow then you just lost 6k flat out.
I'm currently looking at scrypt mining ltc and converting to btc. Buying preconfigured miners isn't all that profitable, but if you configure one yourself then the barrier to entry is slightly higher and the cost slightly lower. It works out to be a small profit.
Honestly, Bitcoin mining is not profitable anymore. Any coin's mining returns good ROI in its initial stages.
Except that it is...
Buy a Cube, run it for 2 months, sell the Cube. You will end up with more BTC than you started with. I guarantee it.
That is IF you can get a cube right this second.
How long before those cubes ship?