1: I did not explain myself clearly. What I meant is: when more and more bitcoins are being used for regular economic transactions, the proportion of bitcoins used by speculators is, by comparison, decreasing. And the smaller this proportion is, the less volatile the currency is.

2: "encouraging hoarding": no, this is not what was observed in practice with Bitcoin. I can't remember if it was Bitpay or Coinbase, but they have explained in a blog post seeing the exact opposite effect: during a Bitcoin bubble, people tend to spend or sell more bitcoins (to cash in on their newfound fortunes).