To counter your anecdotal evidence with my own, I know a fair few people who have bitcoins and not one of them has any interest in the fact they can be used to

To counter your anecdotal evidence with my own, I know a fair few people who have bitcoins and not one of them has any interest in the fact they can be used to buy drugs. Of the people I know It's roughly an equal split between speculation on its value and longer term interest in its potential as a low friction, decentralised currency. Not to say it's not some peoples motivation but I think that they're probably in the minority. There was a piece which was on the front page of HN a while back (can't find the link right now) which estimated the total revenue going through silk road and it was a fairly small fraction of the total bitcoin transaction volume if I remember rightly.