I took one more of those silly, but sometimes recognised, language exams, because my university let me do it for free due to some programme. This one was in Turkish, and now I’m certified. But because the exam was for the “A2” level, I think it’s fair to say I’m a certified Turkish non-speaker. A2 really really means you can’t speak the language. (So what’s the point?)
I also have these certificates in Spanish and English (both corresponding to level C2 according to wikipedia chart) that say that I can actually speak, and even teach the basics of these languages (but don’t worry.. I have not the slightest idea about teaching), and I guess these could be useful — but have never been useful so far.