The score might have some value as one of many pieces of information...certainly not absolute, but then neither is hull speed as generally calculated. As well, there is another formula frequently used to postulate how comfortable a boat might be at sea which would be subject to so many variables that it can only be taken as a very rough indicator.
I suppose if the person who developed the formula allocated the same weight to each predictor as the person who was interpreting it, the "score" would be of some value. Sailors being the obtuse lot that they are however, that is not likely to happen too regularly. The criteria that determine seaworthiness vary widely, and are usually based on individual experience.