Questions on Stack Exchange sites are not for a continuous feedback between the OP, and the users who answer the question, or would answer the question: The OP ask the question, and users answer. If the question doesn't contain enough information, users will ask in a comment what they need to know to answer the question. At this point, once the necessary information is given, the OP should not ask questions to who asked more information.
The continuous feedback between who asks a question, and who replies is typical of forums, which don't have a strict Q&A format; as a matter of fact, there isn't a distinction between comments, and answers, in a forum.
Probably a lock in this case is too much, but it avoided somebody would answer the question without reading all the information the OP provided in the various comments s/he wrote.
The bad of the lock is that, when it expires, nothing is changed: The information provided in comment is still only in comments. If somebody would answer the question after the lock expired, s/he would need to read all the comments to be sure s/he didn't miss any important information.
It would be good if there were a lock that doesn't permit to add new answers, or new comments, but allows the OP to edit her/his question to add the information given in comments.