I'd be curious to see how they handle the back end, especially as some others pointed out it does make calls that seemingly require some hook into the OS. As for its usefulness, I doubt it will really take off beyond being a decent prototype. It relies on image matching so if you use and change a custom icon set all your scripts would be kinda worthless. Same goes if the programs you are "screenshot scripting" receive a major overhaul in the GUI department. Until it can address those issues, I doubt it will really take off.