Example: Comparing the suitability of different solutions (kinds of cameras A,B,C,D) with a problem space (personal interests).
Of course, it's easy to tweak the values in the chart until it says what you want it to say. ;^)
I note that Excel doesn't smoothly join the ends of smooth curves: the first derivative, per dr, of the curve function isn't smooth at the join point. Tsk tsk.
I'm not sure that I like my breakdown of categories... I think I will try and come up with something cleaner.