1 - It absolutely could be speculators, the amount of money in this market is a tiny tiny fraction of the value sloshing around in the world looking for someplace safe from devaluation or confiscation to hide. Right now it's hard to buy bitcoins, but it's alot easier than it was last year and next year it'll probably be easier than it is now, or illegal.
2 - Satoshi's dice is a major source of BTC traffic, are you remembering to factor that in?
Certainly good points. I had considered Satoshi dice as a major contributor of the BTC transactions, but without doing any real analysis I assumed that it would be a small percentage of actual coins being sent. At the current numbers, the average transaction size is around 16 BTC.
I contributed to SD for a bit just a learning experience. I probably did around 30 transactions, lost half of the 1 BTC I was gambling with. That's a lot of transactions (in aggregate), but a very small amount of actual BTC (even in aggregate). 7% of the entire market cap of BTC moved around in the last 24 hours.
