Here are some reasons I believe -- as a Mandarin speaker of nearly 30 years -- you should consider learning the language as well:
Chinese matters more than ever before. With 1.3 billion Mandarin speakers at home, and several million more speakers living in nearly every country of the world, Chinese is one of the most widely spoken languages on earth. It's also one of the most popular languages on the internet (Chinese love the internet and have taken to social media with a fervour that is hard to match anywhere in the world)
It's enormous fun. Learning any language requires a lot of time and effort, and Chinese is no different. But mastering it shouldn't be seen solely as a chore. Learning Mandarin -- and especially using it in real situations -- can be a lot of fun. Besides being able to order off of a restaurant menu and knowing what I'm actually about to eat, or reading a news article without having to run it through Google translate, Chinese is a virtual sandbox for amateur linguists like me who enjoy mashing up meanings and playing with puns.