Investing involves more than putting all your resources into one pipeline. While we definitely purchased large amounts of BTC at the time, mining helped offset the long term risk associated with market volatility. Mining provided steady and better predictable results to support the uncertainty therein.
There's 2 ways to get bitcoins, buy them or mine them. I'm having a hard time seeing how getting 46 BTC rather than 70 BTC is offseting the risk. Why would you want to mine less than you can buy?
This is exactly the question we asked ourselves when KnC first arrived on the scene... the price was too volatile to know what one would profit from it in the timeframe the miner would be running; Gox had just spiked from $38 - $260 then plummeted, then back to $140, then tapered off in a suicidal manner before adjusting to a (+) longer term trajectory. Our thinking was dropping $7k without knowing where the buyin leads was more risky than (could have been 70btc or 53btc) purchasing a miner which was a more predictable speculation (and we had already had success with)
Again this is hindsight and the question would hold very different meaning if any number of crazy things happened to the market in the interim
There are also stages of adoption some bitcoiners go through which factor into my learning experience:
'I believe this is going to be the best thing in the world!'
'Wait what about all this other technical stuff?'
'How do I get as much value as possible then turn it back into fiat currency?'
'Holy crap, I'm never day-trading again'
and finally 'Oh, so if I just hold it everything works out?'