Detritus, the "Japanese" tag is usually reserved for movies produced in Japan, and does not claim to identify the starlet's ethnic heritage. In contrast, the "Asian" tag goes to tell you that the actress is of Asian background. If you have seen a Japanese movie, you will know that it's a decidedly different genre than mainstream American porn, with the actresses taking a much more passive role. Some people might be searching for that specifically, and the tag is meant to come in handy in those situations.

Detritus I think you must have been feeling particularly jaded not to get off on this. Kaiya is a pretty girl with a nice body and her bolt ons are actually quite attractive imo. One slightly odd aspect of the scene is that she will often do anal, but here she only allows her ass to be fucked with a toy. She must have looked at Pirate Guy and the Prison Tattoo Guy and thought 'no fucking way'. Worth a look if you like Kaiya, but not as good as the Roxy scene.

To add to what ths4prn has said, the Japanese tag usually means (to me) cute Japanese girls who spend the scene squealing and crying like they're in pain, which is a shame because I like the way they look but crying is a turn off.