J-rock would still be important to me. I love foreign languages, especially asian ones. Artists like Weiss Kreuz, Dir En Grey, and Malice Mizer have different backgrounds and overall sound than most of the english music I listen to.
It does matter what the artists I listen to look like because I was brainwashed by society as a child to stereotype people. Even a blind person can stereotype people by looks. Most blind people can tell what a person looks like by feeling them out or by a description, and can distinguish physical attributes. If Gackt was as homely as could be, I could like him less, but I wouldn't dislike the music on that account. I still like Tenacious D, even though people think Jack Black is homely and obese.
The look of a band does influence me. If the message of the band matches how they act and look, I'm more likely to think they're cool. With a band like Malice Mizer, their sound is ethereal and somewhat circus-like. The fact that they dress outrageously gothic and wear makeup fits the circus theme, so I am more likely to like their music. On the other hand, I'm not a fan of the band Good Charlotte because their message doesn't match the way they act and look, so I therefore don't like them.