That pretty much sums it up. The author says rather early in the article, "At this point, I am by no means a full time developer, and I'm not even sure I could

That pretty much sums it up. The author says rather early in the article, "At this point, I am by no means a full time developer, and I'm not even sure I could call myself a hobbyist. But thanks to the resources I present in this article, I have moved beyond the point of basic knowledge." So this is basically a list of languages they've found to be the most useful at their (low) level of expertise, and very likely this holds true for their worksite, which is a sample size of one.