My takeaway was that they wanted to show that anything can be made draggable, i.e. isometric blocks created using CSS transforms. The browser actually maps mous

My takeaway was that they wanted to show that anything can be made draggable, i.e. isometric blocks created using CSS transforms. The browser actually maps mouse/touch events from the transformed space back to the untransformed cartesian x,y point. In other words, if I scale a 100x100 <div> 3x then hover exactly in the center of it, I'll get 50,50 regardless of the scale/skew/rotation/matrix. This is really useful for collision detection, which they are trying to demo.