Because there's no option key on Windows and existing modifier keys do not produce anything similar. For copyright I'm using © and if I would need it outside of HTML, probably I'd google it and copy-paste from browser. You are thinking that it's easy to type those weird character for everyone, it's not easy. Probably easiest way is to use some European layout and then spending rest of year trying to remember foreign mappings which don't even correspond to printed letters on keyboard.