The stock answer as to why we learn languages in school is often to broaden childrens horizons, and also to offer them benefits in later life - employment, travel, all of that.
Given Chinas ascendancy in recent decades, and likely growth for decades to come, it seems to make perfect sense to me to consider offering mandarin on the syllabus. Plus, as you say, a challenge and an adventure.
I do know from personal experience that having the merest smattering of a language and making the effort to use it can make all the difference in securing business contracts and making friends :) Which is why I can make myself understood in French, German,Spanish and at least say some real basics like hello and 2 beers please in Chinese and Japanese :)