I think it's kind of funny though because, AFAIK, it doesn't happen the other way around. Japanese and Russian keyboard enthusiasts don't go out of their way to use keycaps with Latin sub-legends on them just because they think they look cool.
It's not quite the same thing, since the standard in Japan is to have both Latin characters with hiragana sublegends, but anecdotally I have met quite a few Japanese people who go out of their way to use keycaps which
only feature the Latin characters and omit the hiragana sublegends, because they think it looks cool/clean. On the other hand, I have never met a Japanese person who wanted a hiragana
monolegend set, although that would be at least as clean as the Latin monolegends. I think this is partly a function of kana input methods being relatively minor in Japan (most people use a romaji-based input method so the Latin characters are actually more useful), and partly because they do think all-Latin looks cooler than all-Kana, which to a Japanese eye can probably look a bit babyish.
For my part, I do type Japanese using the kana input method, so I actually get some utility out of the kana legends, but given that I touch-type in both languages it doesn't matter too much and I definitely make the decision based more on aesthetics than utility. I tend to prefer monolegend sets -- either Latin or kana -- but the fly in the ointment for me is that it's very hard to find a Latin monolegend set which supports the JIS layout (eagerly awaiting
GMK JIS!), so I end up with a lot of kana monolegend or sublegend sets as those are the ones which support my layout. Hopefully that will change as people become more aware of what JIS support entails and kits like GMK JIS open the door for future sets to make use of JIS-compatible moulds.