That doesn't mean anything, or rather, it only underlines what I said. One more reminder to Sasuke he isn't so tough yet, one more reason for him to force himself not to rely on anybody, especially somebody as weak as Karin (in battle). If you know you have a healer at hand, you can use strategy involving healing afterwards. If you don't have a healer, you must do things so you don't need one.
Considering the dodgy Nature of Sasuke's quest against Konoha (although we don't yet know the details nor might he know them himself), having friends tagging along is a bit questionable in any case. It makes no sense. He has got nothing to do after the mission is finished, having dedicated himself to revenge, so why should uninvolved people be involved in the first place? As tools, nothing else.