A pet theory of mine is that they get so much attention because the Japanese held onto feudalism far longer than the colonial powers. As such, the colonial representatives attached some romanticism to Japan and the Samurai.
Something similar laid the foundation for the troubles Iraq has faced to this day, if Adam Curtis is to be trusted.
http://www.bbc.co.uk/blogs/adamcurtis/entries/2989a78a-ee94-...
I think that's a part of it. I think that the other commenter is also correct in that the "far east" has some kind of romantic draw in the western mind.
There's something compelling about people who would willingly die before violating their principles. Even if I don't like it, even if I don't agree with it, I can respect it.
Even when we were at war with Japan, there was a kind of grudging respect. Sure, they were dehumanized in the wartime propaganda and depicted as incompetent or inept in our media, the west was so terrified of them that we interned American citizens who were as little as 1/4 Japanese.
With that said, knowing Western designs of weapons is also extremely interesting. The progression of simple sword -> sword+crossbar -> sword+ crossbar + ring guard -> Rapier -> Basket-hilted sword says a lot about Western Martial Arts (aka: Fencing).
At some point, people figured out that grabbing the crossbar was more comfortable and more precise. So additional protections needed to be added to the top of swords (finger-rings / sweepings).
The full anatomy of the Rapier is astonishing. Every part of the weapon serves a purpose.
Even then, Rapiers were mostly status symbols for the rich. Weapons of War were far more simple and practical. (Well... not always: Landsknechte Zweihander == lulz. They probably discontinued that weapon because it was too expensive, heavy, and unweildly. But man, what an awesome looking sword )
On the article itself, while it's a nice list, it perpetuates some myths about the weapons in question (e.g. that katana was in someway superior to western swords -- high quality specimens on either side would probably be pretty closely matched), and has some fairly glaring admissions (e.g. the yari (Japanese spear) which was one of the most common weapons among footsoldiers for a good deal of Japan's history).
I guess Zweihanders were ultimately still "too short" for real warfare though. Practically speaking, by the late 1500s or so, people only used Halberds and Polearms (ie: English 18-foot Pikes and whatnot). So perhaps it is more accurate to say that Zweihanders were not "unwieldy enough". In any case, Zweihanders only saw use in a period of one century or so... from the late 1400s through the mid 1500s.
With that said, Pier Gerlofs Donia's Zweihander was 6.6kg (~15 lbs) and 2.15m (7 feet) long. Zweihanders definitely could go above and beyond 3kg.
As far as Yari, yes, that is the most glaring omission in the article. Fortunately, the Naginata (arguably a kind of Yari) has representation.
As for the disappearance, I think it had more to do with improving firearms making heavy armoured shock troops impractical, and armies becoming much larger things mostly composed of musketeers with relatively limited training (rather than the smaller armies of very well trained professionals like landsknechtes). The pike disappears fairly soon after, when infantry switch to using bayonets to ward off cavalry.
They don't "seem" foreign, they ARE foreign.
Unless you happen to live in the far east.
Timing may also be a factor. Most western martial arts fell into obscurity and then oblivion centuries ago, while many of these obscure Japanese weapons were still in use well into the nineteenth and even twentieth centuries. Even if Japanese martial techniques had not been valued and maintained, they still would have been in living memory when chambara flicks became popular. For this reason, their portrayal in film has few rivals in Western cinema.
There were a few western martial arts that survived to modern times. Boxing was one, and fencing was another. Fencing certainly had it's heyday, both on the Shakespeare dominated stage and in the golden age of Hollywood thanks to great fencer/actors like Basil Rathbone, but the style of fencing practised was only appropriate to a select few historical settings. Fencing is descended from a duelling discipline and isn't really appropriate in a battle setting or even a fight between commoners. Films where it is appropriate are made so infrequently that actors rarely study fencing at all, let alone enough to become masters.
This is probably why Hollywood embraced Hong Kong fight choreography so enthusiastically in the seventies. It allowed them to fill in the holes left by the death of most Western martial arts with something that was flashy and graceful. Audiences hungry for more Eastern martial arts have naturally consumed a lot of films made in Hong Kong and Japan, and this probably fuelled their curiosity about Japanese weaponry. The fact that Hollywood had to import fight choreography probably also gave many the notion that Eastern martial arts were superior to anything in the West, when the truth is that it was simply better maintained, thanks to cultural values and the relatively late dominance of firearms in the East.