Americans prefer use a more acting, motion style. most frames are different
since most of this animation happens overseas, there's a lot of hands-off direction which can lead to some weird mistakes. less so now because its been going on so long.

in anime, its more keyframe/pose based they can afford to be more detailed, but because of tight budgets and schedules, not a lot of actual animating gets to happen. Its more about economy. Some shows have A LOT of still images and recycled animation.

its just two sides of the same coin. I don't prefer Ninja Scroll over Steven Universe. neither is better, just different.