Different regions have different laws on patent rights, so if you want to apply for a patent in that region, you need to follow the relevant laws and regulations of that region. After authorization, you can only use the patent right in the region where this law applies. I think this is regionality.
The simplest example: if you apply for a patent in the United States, you can't write a document in the way of China's patent law, let alone in Chinese. You must write the application documents in accordance with the relevant laws and regulations of American patent rights and write them in the official language of the United States.
China seems to have a legal system with four kinds of patents: Chinese mainland, Hongkong, Macau and Taiwan Province Province.