[kyazawa]

I think J-Pop in general tends to create interest through composition (fast and complex chord changes, syncopated melodies with lots of movement) compared to Western pop, which tends to create interest through vocal performance. The characteristics of J-Pop mesh really well with Vocaloid where the voice itself is not that interesting to listen to but you have more composition possibilities for fast tempos or wide pitch ranges that wouldn't be possible with a human singer.