Oh, it's much better than killing them. If they're nice, then you'd feel bad about killing them, but still want to tease them a bit because they're so cute when they're angry. And if they're shitheads, they deserve all the suffering you can muster, so you don't want to give them the mercy of a quick death.
Come to think of it, even in my abyuse stories, I'm not sure if I've ever had a human kill a yukkuri other than to feed to a predatory type. Well, no, in the "Single Mothers" story, Alice's children died to a human, but even that one thought it was a mercy killing because they were premature. And...I guess the anon in the experimentation chapter did kill the Kimeemaru simply for thinking it was an equal to him rather than a tool. But overall, usually abused yukkuris are left alive to be killed by shitheads in my stories.