have you twatted?

Among the many intersting add ons to twitter is a neat little thing called twitpay.  Created from a business creation competition (read 54hrs. nothing to operational) twitpay allows you to pay via a twitter post.  All the payment is handled through your amazon payment account which is basically anyone who has ever used amazon.  This seems like a neat idea.  In theory I could walk into your coffee shop and pay you via my phone.  I think we're still in the super early phases of electronic payments, especially here in Erie, PA.  Has anyone actually used this or heard of a real word example?  another benefit is that all your payments would be visible as it is a public tweet.  So your $3 for coffee and $15 to dave for weed would be able to be seen by pretty much anyone in the world.  Thoughts?