> With a small light source even a small change in position on the surface has big effects on the light’s visibility – it quickly becomes fully visible or fully occluded. On the other hand, with a big light source that transition is much smoother – the distance on the floor surface between a completely exposed and completely invisible light source is much larger.

This part of the demo illustrates the point vs area light issue really well. In designing practical 3d scenes and selecting tools, we would often prefer to use 2d area or 3d volumetric lights over point lights. Difficult problems like hard shadows and hotspots in reflection probes are magically resolved if we can afford to use these options. Unfortunately, in many realtime scenarios you cannot get access to high quality area or volumetric lighting without resorting to baking lightmaps (static objects only; lots of iteration delay) or nasty things like temporal antialiasing.