The author proves his own point by using C# as an example for a "boring and similar" language; he clearly doesn't know the language well enough if he truly believes that. That being said, there are two reasons you would want to learn a programming language: to add it to your tool set or to learn the concepts behind it, either for personal gain or to apply those concepts in other languages. I really don't think I will…
Other than that, I completely agree with your thoughts on this.