This question belongs to the most common in an interview. They use it everywhere. Inexperienced HR managers use it to learn something about your weaknesses. And sometimes they use it simply because it can be found on the majority of interview templates. They follow no special intentions with it…

However, the experienced recruiters have another reason to use it. Of course, they are able to assess your strengths and weaknesses without inquiring about it. That's their specialty, the skill they get their salary for. But they use this question to check your trustworthiness and humility, to see if you can assess and admit your own weaknesses.