Interesting, I didn't know this. Let's see what I can add:
Tow Woods, an anarcho-capitalist and senior fellow at the Mises Institute, regularly fills in for Peter on his show. He's really quite interested in Bitcoin and while he reserves judgement on the technology as a whole (recognising a lack of strong historical parallels and that his own understanding is limited), he has commented on being impressed with the logic and lucidity demonstrated by various Bitcoin proponents (Erik Voorhees is his "go to guy").
I reject Peter's claim that greater merchant adoption will suppress the price. It seems as though he's ignoring why people are holding bitcoins in the first place. I find it almost impossible to justify the assumption that most people will want to reduce the dollar value of their bitcoin holdings as those bitcoins become more useful.