One of the major problems in my experience as a teacher of a "second foreign language" has been the reject of students by forcing themselves more on the subject, because they considered my language (German, obviously..:-) ) as not very useful to communicate in the global world. So, many students take German classes because they "love the culture" or feel themselves better by speaking more than only one foreign language --> In fact, learning German is more a question of social status or private interest than communicative utility.
In part, they are right. Compared to Spanish, French, English, or even Chinese (and Arabic?..), German is not spoken in many parts of the world: And Austria and Swizerland do everything to appear their German as a proper language, as they do not consider themselves too much vinculated to Germany. For example, many German students living in Swizerland find it hard to deal with the famous "Schweizerdeutsch" (Swiss German). So, yes, it is true. German is not used in the major parts of this planet.
But: They forget that learning one language has positive effects on understanding another language. There are studies demonstrating the impressing results of multi-linguistic education. Our brain works on the basis of forming connections and creating "isles of knowledge". As many languages in Europe are (to a stronger or lesser degree) related to each other, we are able to form many "mental bridges" between them. This has a positive effect on our learning process in general. It is very similar to the fact that learning an instrument creates neuronal connections which faciliate abstract thinking and understanding. I notice this positive effect with many German students who are playing an instrument. And imagine...if learning piano and learning a language are related...what about the connection of learning two languages! So, learning German can help to learn other languages and vice versa. This is why students should understand the language they are learning in a more global context - by considering German as being part of their language studies in general. For example, when they are studying English, the strong relation to German can help to understand the meaning of the English words and grammar better. And even if we want to learn a language which is not so closely related to German...discovering the differences also helps to clear up our focus on the language we are studying. As the German language has a very interesting and complex Grammar system, its understanding can facilitate us to go through the grammar systems of other languages quite easily.
So, as you can see, learning German can help us to communicate ourselves in a globalized world. Now, it is up to you: Try it ;-)