Looks impressive. I'm sure a lot of people will find this useful.

But what about trust? Namely, who does the user have to trust?

I skimmed the website, and it wasn't clear to me what happens when an account is created. Is this an account with the Bridgewalker service? Or with Mt. Gox? Do you have access to the bitcoin transactions involved in using this app? What about the Mt. Gox accounts used?