It was one of the biggest head-scratchers for me for a long time. You can find some modest and realistic explanation in Lyn Alden's book about how btc corrects the gap that had grown up between the speed of transaction and the speed of settlement (we talk about it in the book club someplace) and that will, I believe, be a real change, though what it will mean in practice is hard to say. Certainly we did not live in a utopia when money was sound and settlement and transaction were equally slow.

Mostly, though, I think it's utopian thinking, which is pretty easy to spot and useful to examine critically.