The relevance of the second part of my post was that it is as unrealistic to expect everyone in the world to adopt bitcoin as it would be to expect everyone in

The relevance of the second part of my post was that it is as unrealistic to expect everyone in the world to adopt bitcoin as it would be to expect everyone in the world to adopt the Euro. And thus, relatedly, that currency exchanges would still be needed constantly under any circumstance. If it is cheaper to exchange from bitcoin to fiat than from fiat to fiat, that would be interesting. I would tend to question whether it is a tax issue. Ordering from Amazon used to be much cheaper too, but nowadays it has been collecting sales tax. My understanding is that, for Bitcoin, this process of being made to play by the same rules has already begun.