The article actually talks about the prime validator regex, and goes on to say that while it's an awesome trick, it is not the "best ever" because it has limite

The article actually talks about the prime validator regex, and goes on to say that while it's an awesome trick, it is not the "best ever" because it has limited scope. I for one think the trick described in the article is pretty useful, and might even use it someday (and possibly have already without realizing it).