The key was just an example of what can be done with it, I am reasonably sure that it as more uses than just that, and the reason it's not automatically put together into a solid model is because the guy who did it has skills more to do with the practical side of machining than well, programing. The idea of it is that you should be able to scan basically anything and to relatively high precision (as high as you are capable of printing, pretty much by definition almost) although obviously with limitations regarding undercuts and such, and something are obviously going to need multiple scans and re-combination in some modelling software, because once again, this guy is a mostly a machinist. But hey, it's free, any printer can be configured to do it.