Your comment could be read as implying that Unified Arabic, the subject of this post, must have been useless as an idea because it wasn't widely adopted.
In reality, there are many factors, not only pure practicality, that lead people to reject reforms like these. In the case of Arabic, it was deeply held traditional values; in the case of Hong Kong and Taiwan, well, I imagine it's simply an unwillingness to appear to be aligning with a regime one politically disagrees with.
But if it was such a great idea, why is it not an issue in Hong Kong which does not use it?