Huh ... Well, last chapter kinda creeped me out, but he isn't total trash yet I guess.
And, well ... She's probably better off with his than with any other master. And it's not like he had the power to actually go against the slaves traders, and since he's basically useless on his own ...
However, I surely hope the anime is better than this and that the manga gets better too, otherwise, I don't get how anyone could say that THIS is better than Arifureta.