I would press that button just to make it go away. ;) Not that it matters -- the data matter -- but I can certainly rationalize why such a button would be more

I would press that button just to make it go away. ;) Not that it matters -- the data matter -- but I can certainly rationalize why such a button would be more effective than a standard form submit button: My peripheral vision has seen a hundred thousand form submit buttons by now. I'm not quite as blind to them as I am to standard-sized non-animated web ads, but it's close. And it seems to me that the problem with being a designer is that it's physically impossible to design a web form in less time than the average user will spend looking at it. You will necessarily spend orders of magnitude more time looking at your forms than a visitor will: Visitors don't look at forms for fun. They click through them fast, or they click away from them even faster. If I had to stare at that button for an hour, as opposed to simply finding it and clicking it as fast as I could, I'd design it differently. Which might very well screw it up.