Like its sibling (parent?) script, Naxi Dongba, Naxi Geba is highly idiosyncratic and used mostly for religious writings. Unlike Naxi Dongba, Naxi Geba is a syllabary, but different people used different symbols for the same syllable. This makes it less than ideal as an interpersonal communications medium.
This raises another aspect of the question: “What is a writing system?” Does a writing system need to be shared to be a writing system? If I create a language and only make notes to myself, is it a writing system? What if I then forget what it meant — is it still a writing system? What if I make marks on paper that might be meaningful to someone somewhere in the universe? I do not know the answer to that, and indeed that question might not have a universal answer. Its answer might be as idiosyncratic as the Naxi Geba syllabary.