At a glance, this is a neat concept, but doesn't seem to come at the problem from the perspective of the most common users of music notation (experienced musicians); rather, it appears to have been written by somebody who was frustrated by trying to learn to read music. For experienced musicians, the priorities are a) legibility for sight-reading and transcription (which this system, with indistinguishable sitting/ha…
That does appear to be its origin. And if you take 12 equal divisions of the octave as a given, Clairnote seems more natural. OTOH once you're thinking in terms of a 7-tone subset, maybe traditional notation is more natural. (It certainly is to me, but I haven't given Clairnote a try.) Traditional notation uses the scale degree as the fundamental unit, whereas this uses the 12-edo chromatic tone as the fundamental un…
They aren't indistinguishable when rendered by a computer. When rendered by hand (where space notes have a tendency to float from the line to avoid being interpreted as line notes), the F and G especially would be indistinguishable.