In Japan, all residents (citizens and people living with a visa) have to have a katakana spelling of their name. Web forms usually ask for this (in addition to your name spelled in kanji, which of course is impossible if your name is in latin characters, so you just hope the form accepts latin), and it's used in many other places as well, such as for bank accounts. Sometimes places will take your latin-character name and transliterate it themselves, and then this causes problems when their transliteration doesn't match that of other places. (katakana has far fewer distinct sounds available than most other languages, so the transliteration always loses information, and there's usually different ways to do it.) Even worse, many forms (like web forms) have rather short character limits for the name field, so with a transliterated Western name, it many times just won't fit within the ~10 characters they allocate.