It's just cold(er) weather cows, that why you can get the higher fat content, if you like it that's fine, but this is not something that is remotely unique to Japanese breeds (have you ever had highland beef?) and those type of cuts are readily available for very reasonable prices, at least in the US and Europe.
Personally, I'm a bit indifferent, not in the sense that I don't like beef or that I don't think there's a difference between breeds, cuts or just general quality (however you want to define ti) of the animal, but in the sense that I had sensational beef made of pretty much every style you can think of. And for what it's worth, I had way more of them in Texas than Japan (though obviously, that's both anecdotal and subjective, though I can't lie, I feel like I can win a drunk bar argument about who has the better beef fairly easily).