This question asked for a very basic definition of pairs trading for explaining to laymen. I've seen quite a few other similar questions. I don't think this provides anything of interest to "traders and professionals" working in the industry. This is essentially an exercise in investor education and/or marketing. A google search would have found many laymen-friendly explanations.
I don't think these types of questions are categorically off-topic. There may be times where "traders and professionals" have to explain complex topics to laymen (investors, executives, etc.) and it's generally a difficult task.
However, most of these types of questions (that have been asked thus far) are too broad and it seems the questioner is the layman. A question should be closed as "not a real question" if the entirety of the question is, "explain XYZ to a layman".
The question should be allowed if it demonstrates knowledge of the subject and specifically identifies the portions of the subject that are difficult for laymen to grasp.
Any question that can be answered with Wikipedia deserves to be dismissed. However, if someone can cite an article found with Google, point to a specific part of that article, and then explain why it didn't make sense, then that should be allowed.