I think they changed it to try to improve literary rates? I'm not sure myself; I googled that info. I get their reasoning, but the look of it still irks me, and I do forever feel odd that Taiwan/Hong Kong and China have a written language that they mutually can't even understand at times, despite all having Mandarin as the official language. Of course, I think some political groups in Taiwan are trying to change that as well as a way to distance themselves from the mainland.