I would guess that they are more important for a potential four point race, than a potential two point race. A serious UTMB aspirant, is unlikely to rely on a two point race to make up the numbers. Even so, you do sometimes hear people who have just ran their first ultra, proudly proclaim that they have two UTMB points.
I didn’t have any problems with navigation on the Ridgeway sections of the W 100, and I found them fairly runnable. I think that the event could be undertaken with either road or trail shoes. Obviously there is a lot more ascent/descent on the Ridgeway spurs. The central checkpoint is a logistic strength of this event, because you are never too far from your drop bag, and you can pretty much have as much spare kit as you want.