These music typewriters are certainly interesting curiosities but never really caught on like the advertisements and curious articles would make you think. Music notation is has far more graphical needs than words as the horizontal and vertical spacing of objects have meaning beyond the objects themselves. So spacing on a typewriter like this can be extremely difficult to do well. This is why metal plate engraving was the dominant form of music engraving for a final published product right up until the 1980s when computers took over. It was far more reliable and you could get any level of complexity of notation. It did the same thing as the typewriter, but the human was the typewriter rather than a mechanical contraption.
While the metal-side of the art is lost, the musical and graphical skill required to make the notation still lives on in "engravers" today who do the work on computers. Practically all music notation today is done on computers with the various softwares and platforms out there. Rendering good music notation is a very difficult problem to solve but most of the good engines have finally gotten to the point where any reasonable notation is possible, and even some unreasonable ones. There is little love lost for the old methods of engraving in my generation, especially given how expensive and time-consuming it was compared to today.
Full disclosure, I'm on the Sibelius dev team and have used it for close to 20 years, so I definitely have a horse in the race of which platform is best. But it's clear that with more competition in this small market, each platform is pushing the others to get better and more flexible.