I'm saying that the alleged comma users are actually mixing both dots and commas.
Western keyboards descended from an American layout that's missing the comma. It's common for comma users to use a dot instead, because they don't have a choice. Also, a lot of software will refuse the input even if they go out of their way to write a comma.
China and India have numerous languages with their own numeric representation. It's not really relevant. Don't think for a minute that there are any standard for the entire population.
There are hard limitations in hardware and software that people have to live with. A keypad only has a dot key.