First of all there's no rule that the very first comment to a question has to be an answer, and that it has to be helpful in that instance - there's always the chance that said helpful answer might come further down the chain - had OP replied to the comment.
Sometimes the best answers are born out of asking questions, because often the person asking the question may not be asking the right question (due to not stating all the details, or having incomplete knowledge, misconceptions etc). Regardless, it sparks a discussion, so I don't see the problem, as long as the discussion is taking place in a civil manner and no rules are being broken. Finally, even if the discussion chain that sparked wasn't helpful to OP, it could help someone else. Or at least entertain them. And those who can't be bothered, can always ignore the chain, or even block the person(s) in question. So regardless, I don't see this as a loss or a negative of any sort.