I don't think this is true at this time because nowadays more Q&A platforms improved and allowing users to share their thoughts or discussing with others on questions. Not Q&A websites are just for answers, they can discuss with others if wanted.There can be many answers, comments, replies. However, there is no discussion, just answers to the question.
I have to agree with this opinion, because forum platforms always have more choices and functions over Q&A cms.WIth forums you have alot more choices, so I suggest you a forum
Obviously and it is why Q&A appeared because it is a replacement for FAQ pages.It's best to ask an actual person rather than FAQ's. There is always a question that is not entirely answered by FAQ's.