TIL. That was really interesting.
The short version is:-
Chinese started out all traditional for thousands of years but when Mao was in power he got a bunch of scholars together and simplified the written words to raise the literacy of the country and as you can imagine, learning 10,000 complicated words is quite a task so that was his idea (not only how it looks but there is a strict order how each stoke, cross, dot is written). But during that time in the 50's, the Chinese people that fled from the Communist regime into Taiwan kept their Traditional Chinese, so if you are in Taiwan, all the words on all the newspaper, books are in traditional Chinese.
Same as in Hong Kong, as in the 50's it was under British rule, therefore the whole "modernisation" of the written Chinese to simplified it never happened in Hong Kong and Macau. And anyone from HK will write traditional Chinese. They also would struggle a bit to read simplified Chinese either. Sometimes it is the same word (if it is simple to start off with), sometimes it is "gutted" and leaving a shell…and then you are end up guessing what was removed! Sure you can guess the gist of what the sentence is saying but it's like reading shorthand.
And also, in Japanese, their Kanji characters which is based in Chinese characters are based in traditional, not simplified.
Lastly, Chinese calligraphy, the art of the written words is all done in traditional Chinese. To me, simplified Chinese is a bit ugly, it lacks the art of traditional Chinese.