>>106139828very true, but you are not gonna get a JP girlfriend or make JP friends if you don't know JP. Also JAV porn is better if you know japanese.
but that's pretty much it, as a tourist you don't need JP, japanese though anime is a means not a cause (anime is not better in JP, but you can learn through anime I guess if you are willing to suffer through barely understanding the language and pausing when you NEED to know), video games can be OCR'd, etc.
Also C++ is a masochistic programming language, Japanese is also a masochistic language, it's not uncommon for C++ developers to learn Japanese once C++ becomes too easy.