I haven't tried it, but I think anything that makes you put in extra time with your fingers on the frets is a good thing.
Many instructors would tell you that practicing getting notes wrong is bad for you. For instance, just about any "sweep picking" tutorial I have ever seen admonishes "don't try to play this faster than you can, building speed without accuracy won't work." So with that in mind, you would want to score high on easy setting before moving on to the next setting.
cosmicconflict, do you find that it is accurate when it keeps score of what notes you got right?