Board Thread:Episode Discussions/@comment-32617252-20180429034507/@comment-1512913-20180429135713

Not the same. Hidan has to acquire someone's blood and it just mirrors the damage between him and a linked target. This one seems to work on a principle of ascension, kill an Otsutsuki > get a power up.

It's pretty much confirmed at this point that Kawaki also killed an Otsutsuki. In that case, the dude must be OP, OR it was a similar case as Boruto, someone provided assistance and Kawaki just landed the finishing blow.