Haku used his Ice Mirrors technique to increase the speed of his movement, but he more or less "killed" Sasuke using senbon (even though Sasuke came back to life), so it's not really limited to "less important ninja."
Also, Itachi killed hundreds of his fellow Uchiha clan members using shuriken and kunai. The Uchiha were considered geniuses throughout the village and although they were expendable characters you can clearly see their bodies on the ground with kunai and shuriken sticking out in Sasuke's flashback in the anime.
But weapons in general are primarily an accessory to the ninja in the naruto universe, one which tends to require a lot of deception and planning to be used successfully. I think it's also probably cheaper, in battle, to use a kunai or shuriken as a distraction than a jutsu which costs chakra (a limited resource) which is why we see them used like this so often.